As with much of the content in this game, different team compositions fulfill different purposes depending on the demands of the stage you’re trying to tackle. However, it’s generally unrealistic to be investing in more than 5 or 6 characters at a time, as Silver Coin and EXP Potion costs for upgrading become an incredible roadblock after around Level 40. Hence, it’s important to pick what you want to invest in from the beginning. This team builder is formulated based on the Demon Spire. As the benchmark for what is currently the hardest content in this game, this can also be seen as a cookie cutter for builds that can typically beat all other available content as well. A disclaimer before we start: for some stages, specific characters that may not be useful otherwise can actually be the most efficient strategy. However, the general rule of thumb is that two healers are absolutely necessary for endgame content, and that the other three slots in your team will be filled with either 3 attackers or 2 attackers and 1 protector (note, again, that I use the term “attackers” loosely, it encompasses obstructors as well as supports that don’t heal). Individual character choices will be explained below:

Dragoon Iris

An auto-include in almost any team. The crown jewel of the attacker class isn’t an SSR or SR character, but a mere R. Just by reading her skill descriptions alone you should get the general idea behind why she’s a completely broken character, but if you’re still not convinced, I’ll explain. Her Ultimate Ability, which stacks with itself, deals a whopping 1400% Attack Power to ALL ENEMIES over 20 turns at Bond 5 (which you should easily already have) per cast on a 5 CD, which is reduced to 4 if you upgrade her to 3★ (which costs only 42 Memory Orbs). If you decide to raise her to 5★, she gets a permanent 20% Attack Power buff every time you cast her Ultimate Ability, stacking up to 5 times, which is one of the strongest 5★ abilities in the game. However, a 3★ Iris should be sufficient to complete the entire Spire (and the rest of the game). To compare this with conventional SSR attackers, let’s take a look at the top two SSR damage dealers. A Bond 5 Iblis deals 560% damage to a SINGLE TARGET on a 3 CD, while a Bond 5 Idol Iblis deals 1356% damage to a SINGLE TARGET over 6 turns on a 6 CD at Bond 5. It’s pretty obvious by now that the amount of power Iris brings to your team is irreplaceable, so do yourself a favor and invest in her from the beginning.

Healers: Choose Two
Idol Noel
Phasi Princess Lulu
Nether Queen Daphne Bloom
Demon Maid Aiko
Head Military Nurse Irene

I’ll go into each individual character’s details in a bit, but if I had to rank the combinations, it would be Noel + Aiko > Noel + Daphne = Noel + Lulu > Daphne + Aiko > Daphne + Lulu > Lulu + Aiko. The reason why you need two healers in the Spire (and hard content in general) is because battles are generally long and you will need to sustain your team for many turns (which coincidentally is why Iris is so good as an endgame attacker since she gets full use out of her Ultimate Ability).

Idol Noel

By far the most broken character released so far, and by a large margin. The amount of utility she provides overshadows even the ridiculous damage output Iris brings, which is saying a lot. In essence, she is all three SSR/SR healers amalgamated into one character, but also doing all of their jobs better. She has a stronger version of Lulu’s team attack buff on her Basic Attack, better passive healing per turn on her Ultimate Ability than Lulu’s, a cooldown reduction mechanic on her Ultimate Ability that’s more versatile than Aiko’s, and at 5★, an additional shield that surpasses Fiora’s Ultimate Ability, literally the best Leader Ability in the game… the list goes on. Unfortunately, she isn’t available anymore, since she was a limited summon from the Valentine’s Day event. The combination with Aiko assures immense versatility, as Noel can either be in position 1 (offensive) or 3 (defensive). In the offensive build, you put Iris in position 3 and constantly reset her Ultimate Ability to quickly stack damage, while the defensive build with Noel in position 3 allows her to use her Ultimate Ability on a 3 CD (even more efficient than if she was the Leader), thanks to Aiko resetting her Ultimate Ability and Noel reducing Aiko’s Ultimate Ability CD by 1. The combination with Lulu on the other hand typically necessitates Noel being in position 1 for her Leader Ability as having her Ultimate Ability on a 6 CD hurts your team a lot. This version is also likely easier to use and provides better base healing before turn 5, but you will get more options and mileage out of Aiko.

Phasi Princess Lulu

One of the strongest SSRs from the Eternal Summon happens to be the princess of the Human Realm, and for good reason. Her overall team healing output is the highest in the game (Noel has higher ratios on her Ultimate Ability, but Lulu also heals on her Basic Attack), while also providing a valuable attack buff to the team every time she attacks. Using her in conjunction with Aiko more than doubles her team healing, allowing you to survive any attack that doesn’t instantly kill. With Noel, you get attack buffs for the entire team twice, with each of them also amplifying the other’s team attack buff on Basic Attack. A must-have if you started playing after the Valentine’s Day event or if you lack Noel.

Nether Queen Daphne Bloom

Tied with Lulu in terms of overall power level, Daphne has the highest shielding potential in the game. Her Leader Ability is incredibly powerful, possibly tied with Noel in terms of generalists, and her other passives are also very strong. Her attack buff only comes when she uses her Ultimate Ability, unlike Noel or Lulu, but she makes up for it by scaling extremely well with higher Bonds, gaining -1 CD at Bond 3 and a massive 50% team attack buff at Bond 5. When using her together with Aiko, it’s usually better to either leave Aiko in the third slot or give it to Iris, as resetting Daphne’s Ultimate Ability is often overkill, with the shield expiring before you can make full use out of it. As the Daphne + Aiko combination is slightly more valuable than the Daphne + Lulu or Lulu + Aiko combinations, you may want to go for her instead of Lulu.

Demon Maid Aiko

We’ve already talked about Iris, but Aiko is the other half of the tag team named “broken characters that are also free”. No one else has her unique mechanic of position-based buffs, and her 4 CD reduction for the target character in position 3 might as well be a full reset for most characters, which also provides an additional 50% Attack Power to the target character for one turn. I’ve already discussed the synergies with the other two healers, so you should get the general idea of why Aiko can be incredibly useful in both offensive and defensive team compositions.

Head Military Nurse Irene

Irene is different from the other Healers before her because she doesn’t heal the entire team at once, but rather only one target at a time. However, she has the most potent heal, with a whopping 150% ratio on her basic heal. This has extreme synergy with Satan’s Leader Ability, which permanently taunts all enemies, meaning that you can use Irene with practically no drawbacks as you’ll generally ever only need to heal one target. Her Ultimate Ability provides a single target with the strongest heal over time in the game, as well as an incoming damage reduction buff. When used with Satan, Irene can defy the two healer rule by carrying the healing job all by herself, allowing you to run three attackers on top of Satan.

Attackers: Choose Two
Archdemon Satan
Archdemon Iblis
Idol Iblis
Magic Automaton KS-VIII
Elf Queen Salucia
Archdemon Ba’al
Dwarf Queen Lana
Snake Queen Mesmiia
Risen Princess Chizuru
Easter Bunny Satan
Sword Saint Minayomi
Demon Mage Manuella

I consider any character that deals damage to be an “attacker”, which is why this list has protectors and obstructors as well. It doesn’t really matter what you pick from this list (any 2 will do), the only caveat is that you shouldn’t have more than one Protector. However, exactly because there are so many Attackers, you can probably afford to pick the better ones to fill these slots in your team:

I won’t go into detail about every single character as most of them fulfill the same purpose anyway, though I will talk about the key choices as well as specific synergies below.

Idol Iblis

The second limited edition unit from the Valentine’s Day event; her competitor may have taken the spot of top idol in more ways than one, but Iblis is no slouch either. The Chinese wiki says she is “written as an obstructor and read as an attacker”, which aptly sums up her purpose – to dish out massive amounts of single target damage. Her Basic Attack and Ultimate Ability apply fully stackable debuffs that deal significant damage over time (200% Attack Power over 4 turns for her Basic Attack, and 831-1356% Attack Power over 6 turns for her Ultimate Ability). This is reminiscent of Iris, but much more focused and even more powerful against single targets in a pinch. If that wasn’t enough, her Ultimate Ability also applies a stackable 15% Attack Power/25% Recovery Rate debuff on the target for 6 turns. Perfectly usable at 3-4★, but 5★ is definitely worth it as well for the 2 CD reduction that turns her into even more of a monster. Although Spire 40’s Lana now cleanses damage over time debuffs, Idol Iblis (and Iris) are still viable, and the best choice, pretty much everywhere else, leaving her at the top tier.

Archdemon Satan

The only Eternal SSR protector is also an extremely powerful and useful character, that straight up wins you fights on her own in some cases. Her Leader Ability puts her in Taunt permanently, which means all enemy attacks are automatically directed towards her, and reduces her damage taken. However, she can still be very useful even without being the party leader, as her Ultimate Ability allows her to reflect tons of damage to the enemy team for 2 turns, while absorbing the brunt of enemy attacks for your team. Satan adds another layer of versatility to your team by providing an incredible bulwark that supports the double healer composition intrinsic to the meta if you choose to use her as your leader, replacing the more offensive oriented teams that use either Noel or Salucia as their leader. Satan has become more relevant than ever now with the latest Spire bosses requiring her presence. If you manage to get her to Bond 5, she can permanently taunt the enemy team with her Ultimate Ability, essentially giving you her Leader Ability without using the leader slot in your party. Incredibly useful defensive character, though she can also be used in offensive compositions to allow your other characters to attack with impunity.

Magic Automaton KS-VIII

With the advent of bosses that cleanse damage over time debuffs, conventional attackers are back in the spotlight. Under normal circumstances, the best of them is KS-VIII, who doesn’t need high Bond to be good (her Bond upgrades are pretty bad anyway), but has an incredibly powerful 5★ ability. Ignoring Bonds, KS-VIII has the highest damage output in the game, both suited for short battles (with her Leader Ability) and long battles (with her Ultimate Ability giving her an additional 200% Attack Power once fully stacked). This character is definitely worth investing in as insurance for the future, especially if you have limited resources to work with.

Archdemon Ba’al

For the same reason that KS-VIII has quickly entered relevance, Ba’al offers immense direct damage output, allowing her to counter bosses that cleanse damage over time debuffs. However, she is generally the more expensive option compared to KS-VIII, as KS-VIII should outperform Ba’al until she gets Bond 5. This immensely powerful Bond upgrade reduces her Ultimate Ability’s CD by 1. Combined with her 5★ ability, which also reduces her Ultimate Ability’s CD by 1 while increasing the target’s Ultimate Ability CD by 2, she essentially becomes Manuella, but with SSR stats and scaling, with a 2 CD Ultimate Ability that can be permanently amplified by an additional 125% if you set her as your leader. If you’re able to get her to Bond 5, Ba’al is now an automatic inclusion in your team.

Demon Mage Manuella

If it isn’t clear enough from reading her skill description alone, Manuella’s 5★ ability essentially serves as a permanent silence on the target she’s attacking, because it increases the target’s Ultimate Ability CD by 1 on Basic Attack. Coupled with her natural Bond 5 if you’ve been playing any amount of this game, her damage output is practically on par with other conventional SSR attackers with lower Bond levels. Dark element is a plus because it means that no enemy resists her damage type as well. By far the easiest way to cheese most of the Spire’s mechanics, and indeed most of the game as a whole as well. However, the initial investment in her might be a slight obstacle, though she requires much less resources to 5★ than higher tier characters (160 Memory Orbs and 1 Flawless Spirit as opposed to 430 Memory Orbs and 3 Flawless Spirits for 5★ SSRs). Another weakness to note is that N characters aren’t covered by the Discipline system, meaning that they lose out on 15% in stats compared to higher tier characters. Like R characters, they only have 6 potential tiers as well. Despite these issues, the relatively minimal cost of maxing out this character as well as her utterly broken 5★ ability make her a top choice if you want easy progression. Unfortunately, Manuella has fallen in favor thanks to the introduction of CD change immunity on certain bosses. Most of the content currently in the game can still be completely shut down by her, but the major bosses (Spire 35 and above) that prevent her 5★ ability from working have reduced her viability a little. Nevertheless, she is still very powerful as a standalone attacker, packing a significant punch with her high ratio Ultimate Ability, inbuilt CD reduction, and her “neutral” element.

Sword Saint Minayomi

Apart from Aiko, the only SR remotely worth investing in with the endgame in mind is Minayomi. Her Ultimate Ability places a permanent debuff on enemies that causes them to take 10% more damage per stack, which stacks up to 3 times for a total of 30% damage amplification for your entire team on that target. This is further enhanced by her 3★ ability, which allows her to place a similar but separate debuff on enemies that causes them to take 5% more damage per stack on Basic Attack, stacking up to 5 times for a total of 25% damage amplification for your entire team on that target. Combined, this is a whopping 55% damage amplification for your entire team once fully stacked; she also has respectable damage output of her own as her Ultimate Ability CD is one of the lowest in the game at 3. She is on par or better than the typical SSR attacker, but SRs are very costly to evolve to 5★. A perfectly valid addition to your team if you find yourself out of luck and unable to summon any good SSRs. In other words, you can have a perfectly functioning and endgame viable team with only one SSR – either Noel or Lulu – with the other slots filled by Iris, Manuella, Aiko and Minayomi.

Other Attackers?
Iblis is a very economical investment as her Leader Ability allows her to be used for flash farming low level missions when you have lots of energy to use, and her single target output is still respectable. Salucia should be given special attention as her Leader Ability is decent if you lack Noel, Daphne or Satan, and her general utility in buffing the entire team while having fairly impressive damage output of her own also makes her a decent pick even if you don’t intend to use her as your leader. Chizuru is very average. Mesmiia has now replaced Lana’s spot as the worst SSR, though you should try to use something better than either one, such as Minayomi. Lana’s high Attack Power ratio on her Ultimate Ability is very deceptive; because of its tremendously long cooldown, her overall damage output is half that of Iblis. Unfortunately, Mesmiia is pretty much completely worthless, as all endgame bosses in the Spire are immune to crowd control. You’re generally better off investing in another attacker apart from these two.

Honorable Mentions
The rest of the SRs and some interesting R and N units will be briefly discussed here, but for the most part, you can assume that they aren’t investments that provide valuable returns (unless you really pump excessive resources into them, which isn’t ideal).

High Priestess Fiora: can fill in for either Noel or Lulu early game, but generally too weak for the endgame.
Ninja Ritsuki: has a Leader Skill for clutch situations, and is useful for Spire 20, but not much else.
Genius Tactician Britney: provides good utility in her AOE cooldown increment, but hits like a wet noodle.
Fox Spirit Shizuka: can cheese certain stages with her silence, but otherwise too unreliable for general use.
General Juneau: if you have Idol Iblis, Satan, Minayomi or any SSR attacker, there’s no reason to use Juneau.
Holy Knight Captain Leona: She’s the second best option to Satan, but you hardly ever need a Protector.
Slime Queen Nafrala: definitely the worst SR, you probably shouldn’t waste a spot for her (she cute though).
Phasi Wizard Petra: incredible AOE burst, good for flash farming lower level stages, but can’t fight bosses.
Isori Warrior Kikyou: has Guard Break on Basic Attack at 5★, which can be useful in the future, just not now.

Leader Abilities
If you don’t see a character on this list, it’s probably not worth using as your Leader. Characters are loosely tiered according to their viability.

Noel: the best of both worlds. Faster CD on Noel means faster CDs for your entire team, and her Ultimate Ability healing stacks with itself. The passive healing will also allow your team to survive better before you can get her Ultimate Ability off.
Daphne: Similar to Salucia’s, but only applies to positions 1, 3 and 5. However, the fact that 33% of the bonus is an Attack Power buff rather than simply a Basic Attack buff gives it an edge, as it applies to both Basic Attacks and Ultimate Abilities. Also has an additional 15% buff to Ultimate Abilities for the characters in those positions.
Satan: the premier defensive Leader Ability, which makes her permanently taunt the enemy team. Very brain dead when used on most stages, as long as Satan doesn’t get killed in a single hit and you have sufficient healing to keep her alive.
Salucia: the alternative to Noel, she gives a meaty 50% buff to all Basic Attacks, including ones that heal. The strongest generalist Leader Ability from the Eternal Summon set.
Idol Iblis: a “selfish” Leader Ability that grants her immense offensive power, as it makes her Ultimate Ability instantly usable at the start of each wave and also buffs her (and only her) Attack Power by 50%.
Ba’al: very similar to Idol Iblis as she gives herself 125% Attack Power while reducing the rest of the team’s Attack Power by 10%, but you should typically only be using her if you have her maxed out at Bond 5 and 5★.
Iblis: incredible Leader Ability for both single target shredding and AOE farming, but also another “selfish” one.
Aiko: wish Iris had a viable Leader Ability? This is your “Iris leader”. Solid choice if you want to buff Iris even more with an additional 50% Attack Power.
Ritsuki: useful in edge cases where you need your team to use Ultimate Abilities on the first turn, but no sustained power.
Minayomi: decent offensive option if you have many attackers in your lineup.
Lana: generally just a worse Salucia, you don’t want to run her anyway.
KS-VIII: a massive joke in most cases, but if you can end the fight in 10 turns or less, she may be worth using.

5★ Priority
With how scarce Flawless Spirits and Memory Orbs are, you’re going to want to be careful in picking which characters to get to 5★ first. Here’s a brief list of characters worth evolving to 5★, in order:

Idol Noel: Her 5★ ability is probably the strongest in the game, on top of an extremely overloaded kit by default. The massive shield it provides can be used as a crutch for endgame content that would require much higher potentials otherwise.
Ba’al: Assuming you also have her at Bond 5, Ba’al’s 5★ ability is second to none offensively. Reducing her Ultimate Ability’s CD by 1 (with an additional -1 CD with Bond 5), she will be able to use it every other turn. In addition, the bonus effect of increasing the target’s CD by 2 with each usage practically makes her a superior Manuella.
KS-VIII: The quadruple strike provided by her 5★ ability is a tremendous power spike, which also allows her to break enemy charge-ups by herself. Increases her damage output significantly; if you don’t have Ba’al at Bond 5, this should be your 5★ priority as it is the cheapest way to get a high end single target attacker.
Idol Iblis: The only reason why her 5★ ability doesn’t rank higher than the two attackers above her is that she can’t be used against Lana on Spire 40. Otherwise, it’s as potent as it sounds – she can now stack 30% damage reduction and 50% recovery rate reduction on any target, while also dealing significantly more damage with her CD reduced by 33%.
Iris: Contrary to her immense usefulness typically, Iris’ 5★ ability is in fact not essential. This is not to say that it isn’t good – it’s still incredibly powerful – but with the current game’s content, 3★ is already more than sufficient on her for the most part. However, she’s a viable option to 5★ once you’ve managed to get the others up to speed.
Satan, Lulu, Daphne, Manuella, Minayomi: These all lie in the realm of “good to have, but not necessary”. Satan, Lulu and Daphne can sit at 4★ just for the stats (Satan especially needs them to survive endgame content, while more healing on Lulu or more shield power on Daphne may be needed especially if you lack Noel). Manuella does need 5★ to be particularly useful, so if you chose to go down that path, make sure you see it through. Minayomi is mostly fine sitting at 3★ just like Iris, but pushing her to 5★ is also worthwhile (see the damage chart).

Final note on 3★ priority: Assuming you’re using them in your lineup (which is very likely if you’re following this guide), Iris is the first character you should evolve to 3★ (the CD reduction does wonders), and then it’s up to you to choose between Aiko (for the cleanse on the character in position 3) and Minayomi (for an additional 25% damage amplification on the target she attacks for your team, for a total of 55% combined with her Ultimate Ability when fully stacked). If you’re using another attacker, skip Minayomi, but Aiko is still recommended as her 3★ ability is somewhat useful and she desperately needs the stats to survive.