Guide
How the kit works
Before a fight, Beginning of the End costs 2 Technique Points if it hits an enemy. In combat it gives allies 25 Energy, grants 1 Skill Point and 2 Scourge, and deals Physical DMG at the start of each wave. It immediately defeats normal enemies without entering combat.
Use Let There Be Light to gain 2 Coreflame and hit one enemy plus adjacent targets. Pyric Corpus lets Phainon use his Ultimate at 12 Coreflame. An ability from another unit targeting him gives 1 point; if a teammate casts it, he also gains 30% CRIT DMG for 3 turns. Up to 3 points can overflow and carry into the next cycle.
He Who Bears the World Must Burn transforms him into Khaslana and creates Ruinous Irontomb. Teammates depart while it lasts. Khaslana has 8 extra turns, and at the start of the last one he launches a final hit worth 960% of his ATK, distributed evenly among enemies.
Fate: Divine Vessel gives Khaslana 4 Scourge on transformation. He is immune to Crowd Control debuffs, gains ATK and Max HP, and heals after attacks. If he takes a killing blow, he heals and launches the final hit early, with its multiplier reduced for each remaining extra turn.
During the transformation, Creation: Bloodthorn Ferry gains 2 Scourge. Calamity: Soulscorch Edict gains Scourge based on the number of enemies, makes them act, then counters; Khaslana takes 75% less damage while Soulscorch is active. Spend Scourge with Foundation: Stardeath Verdict. It dispels his debuffs, and spending 4 points adds a hit distributed evenly among enemies.
Build and why
Use four pieces of Wavestrider Captain with two pieces of Arcadia of Woven Dreams. Wavestrider Captain gives CRIT DMG and collects Help stacks when allies target Phainon. With two stacks, his Ultimate consumes them for 48% ATK for 1 turn. Arcadia of Woven Dreams increases damage when there are fewer than four ally targets on the field, which suits his solo transformation.
As Navigator Isee Sees It is another four-piece option. Its Skill and Ultimate damage stacks fit his attacks, though it loses a stack at the start of the wearer's turn or after their Ultimate. For planar ornaments, Rutilant Arena gives CRIT Rate and boosts Basic ATK and Skill damage once CRIT Rate reaches 70%.
Choose CRIT Rate or CRIT DMG on the body, ATK Percentage on the feet and rope, and Physical DMG Boost or ATK Percentage on the sphere. For substats, look for CRIT Rate first, then CRIT DMG and ATK Percentage.
Thus Burns the Dawn is the first weapon choice: it gives base SPD, ignores 18% DEF when dealing damage and grants 60% damage after Ultimate until the start of the wearer's turn. On the Fall of an Aeon builds ATK when attacking and gives a damage bonus after breaking Weakness. A Trail of Bygone Blood is another option with CRIT Rate and Skill and Ultimate damage.
Leveling priority
The game's leveling order is Let There Be Light, Pyric Corpus, Stride to Deliverance, then He Who Bears the World Must Burn. The Skill is your regular way to gain Coreflame, while the Talent governs the transformation threshold and rewards abilities directed at Phainon.
For full ascension, gather 308,000 Credit, Invasive Clot, Ethereal Omen, Echoing Wail and Eternal Lament.
To level all skills, you also need 3,000,000 Credit, Tracks of Destiny, Borisin Teeth, Lupitoxin Sawteeth, Moon Rage Fang, Daythunder Anamnesis, Ethereal Omen, Echoing Wail and Eternal Lament.
Eidolons worth it
For a later upgrade, I would consider Embers of Old Rise Still. It removes the Coreflame overflow cap, gives 6 Coreflame at battle start and adds True DMG equal to 36% of the attack's total damage after Foundation: Stardeath Verdict. That extra damage hits the enemy with the highest HP.
Sky and Earth Churn Mortal Froth is another strong option: Khaslana gains 20% Physical RES PEN, and spending 4 Scourge on Foundation: Stardeath Verdict gives him an extra turn.
Fire and Light Bind Virtue and Vice is worth considering for faster Khaslana extra turns and 50% CRIT DMG for 3 turns after Ultimate. If you stop at E2, E3 through E6 can wait. E3 and E5 raise skill levels, while E4 adds 4 Soulscorch stacks when using Calamity: Soulscorch Edict.
Teams
Look for buffers who can target Phainon before his transformation. Sunday, Cerydra, Bronya and Tingyun are named options. Check which abilities actually target him: those are the ones that can contribute to Coreflame and his CRIT DMG bonus.
A sustain character is useful before the transformation. Huohuo and Dan Heng • Permansor Terrae are options to consider. Healing or a Shield from a teammate activates Bide in Flames for 45% increased damage for 4 turns; an Energy Regeneration effect from a teammate's ability gives 1 Coreflame.
You do not need a particular teammate element to give enemies Physical Weakness inside the Territory. After the transformation ends, Fate: Divine Vessel gives all allies 15% SPD for 1 turn.
Common mistakes
Do not enter the transformation expecting teammates to act inside the Territory. If you transform during an ally's turn, Fate: Divine Vessel extends buffs on that ally by 1 turn and ends their current turn, so pay attention to the timing.
Do not forget Scourge when choosing transformed attacks. Foundation: Stardeath Verdict can spend fewer points, but spending 4 adds its distributed hit. Calamity: Soulscorch Edict makes enemies act first, so account for their actions even with its damage reduction.
Avoid treating all extra Coreflame as stored progress: without E6, only 3 overflow points carry over. Also check your CRIT Rate before relying on the full bonus from Rutilant Arena.
