King in Check, the final Anomaly Arbitration stage, has a reputation for punishing Phainon teams. The 4.6 version of the fight adds an 80% damage reduction shield and a mechanic that can force Khaslana out of his ultimate state, which has convinced a lot of players that the Deliverance route is dead here. It isn’t. A zero-cycle clear is reachable at E2, and it doesn’t require Robin’s true damage window to land.
Quick answer: Run Phainon, Robin, Cerydra, and Cyrene at 16 Cost, open with Phainon’s ultimate on Wave 1, and clear both phases before the first cycle ends — the Battle Over screen should read 0 Cycles Used.
The two teams that clear King in Check at 0 cycles
Two lineups get the job done, and they behave very differently once Phainon’s ultimate expires. The Cyrene build is the deterministic one. The Sparkle build trades consistency for a lower cost ceiling.
| Team | Cost | Behavior |
|---|---|---|
| Phainon, Robin, Cerydra, Cyrene | 16 | Clean 0-cycle. Robin’s true damage is not needed to close either phase. |
| Phainon, Robin, Cerydra, Sparkle | Down to 13 | Still a 0-cycle, but the downtime between Phainon’s ultimates leans on RNG. |
The cost difference comes from a small quirk. With Sparkle in the slot, Robin’s summoned birds actually get to act, which adds damage the Cyrene version never sees. In the Cyrene team the birds sit idle unless Phainon is knocked out of his ultimate state or dies outright — neither of which should happen in a clean run.
Stage mechanics that decide the run
King in Check applies two traits to everything on the field, and both push you toward front-loaded burst rather than a long grind.
| Trait | Effect |
|---|---|
| Hemovore | Each ally loses 500 HP at the start of their turn. This can kill. |
| Scales | Enemies start with 20 stacks; each stack cuts damage taken by 2%. One stack falls off per attack, and stacks reset on boss phase transitions. |
Scales is why multi-hit pressure matters more than a single huge number. Every individual attack strips a stack, so a Phainon rotation that chains skills and meteors is shaving the damage reduction down while it works. Because stacks reset when the boss changes phase, you rebuild that pressure from scratch after each transition.
The stage also throws Manipulated Logos and Imprisoned Mythos summons at you alongside the main boss. They delay actions, drain Skill Points, and mark a target so the boss can apply Action Lock, which stops that character from acting and cannot be cleansed conventionally. Killing the summons restores party Energy and advances everyone forward, which is also the fastest way to remove Action Lock. Cyrene’s Support on the action bar dispels it too, and charges the affected ally’s ultimate at the same time.
Note: In Phase 3, if the summons are still alive when the boss uses Immolate the Heavens, Abandon the World, you eat an Action Lock plus an Energy drain. Blast and AoE damage handles this, since hitting the summons also damages the boss.
Running the Cyrene team at 16 Cost
Swapping Cyrene for Sparkle
Dropping Cyrene for Sparkle keeps the zero-cycle intact and opens the door to a 13 Cost run, but it changes what you have to manage. The gap between Phainon’s ultimates becomes the weak point, and how well it goes depends partly on how enemy actions land.
You also lose Cyrene’s Support as an Action Lock answer, which makes killing Manipulated Logos and Imprisoned Mythos on schedule non-negotiable. In exchange, Robin’s birds contribute real damage, and that extra output is what buys back the cost reduction.
Builds used for the clear
Every character sits at level 80 with a level 80 light cone. These are the numbers behind the runs above.
| Character | ATK / SPD | CRIT Rate / DMG | Light Cone |
|---|---|---|---|
| Phainon (E2) | 3201 / 118.8 | 88.2% / 188.3% | Thus Burns the Dawn |
| Robin — Summeretto | 1843 / 158.4 | 42.3% / 101.8% | Rise and Sing |
| Cerydra | 5134 / 141.3 | 5.0% / 55.1% | Epoch Etched in Golden Blood |
| Cyrene | 1275 / 194.8 | 42.1% / 184.5% | This Love, Forever |
| Sparkle | 1405 / 165.0 | 5.0% / 236.8% | Earthly Escapade |
Phainon’s HP sits at 3816 and DEF at 1266. Robin runs 8691 HP and 929 DEF, Cerydra 4325 HP and 1408 DEF, Cyrene 6216 HP and 1045 DEF, and Sparkle 5675 HP and 1105 DEF.
Why a Phainon run fails here
Most failed attempts trace back to a small number of causes rather than a build problem.
- Leaving Manipulated Logos and Imprisoned Mythos alive, which feeds Action Lock and drains Skill Points.
- Single-target damage that fails to strip Scales stacks fast enough, especially right after a phase transition resets them.
- Idle turns during Phainon’s ultimate, which is the only realistic way the ejection mechanic triggers.
- Hemovore stacking with boss damage on a squishy support that had no cover.
The 80% damage reduction shield is the genuine obstacle, not the ejection mechanic. In practice the transformation stacks are reduced by every attack you land, so a team that keeps hitting rarely sees the ejection at all.
Confirming the 0-cycle clear
The result screen is the only confirmation that matters. When the boss dies, the Battle Over screen reports 0 Cycles Used, and the stage credits all three objectives at once — victory within 6, 4, and 2 cycles. If the counter reads 1 or higher, the clear still counts for the lower objectives, but the run was slower than the rotation intends.
Higher-cost setups have room to spare. A 27 Cost clear at Plight difficulty is on record with E6S5 Phainon, E6S1 Cyrene, E2S1 Cerydra, and E2S0 Robin, and a 48 Cost Phainon sits close to a zero-cycle rather than close to failing outright. That gap between the two ends of the investment scale is the real story of this stage — the fight is hostile to Phainon by design, but it has not locked him out.
