Victor Gideon

Chapter: 15 · ARK: Finale
Where: The arena below PANDORA, in the Elpis chamber: small and rubble-strewn in phase 1; in phase 2, very little room in front of a flesh mass on the far wall.

Weak point

Phase 1: his body, especially right after a parry; the RPG-7 he drops. Phase 2: 3 red pustules (head and shoulders), then 5, and the pustule clusters on the floor.

The final boss, only with the Release Elpis choice. With Destroy Elpis there's no fight. You play as Leon. Two phases: a mutated human with a tentacle arm and a Nemesis form (he carried a Nemesis-type parasite). Every one of his melee attacks can be parried, in both phases. After a parry he steps back a pace: shoot him, no need to counter with the hatchet.

Prepare first: spend every credit (power upgrades, ammo, healing), craft everything, repair your Body Armor, upgrade the Hatchet and bring the Mortal Edge for parries. Bring every Requiem round and at least one Stacked Hand Grenade (PowerPyx spends them on the Repository 11 wave; Game8 and IGN keep them for phase 2).

Reward

The good ending and the Hope and Requiem trophy (200 CP).

No published HP. Destroy Elpis skips the fight and still counts as a completed run (including Remarkable Agent on Insanity), but it doesn't give Hope and Requiem or Speed Demon: keep a save from before the choice. Two versions of the killing blow (the Requiem to the head per IGN, Automaton and the wiki; the hatchet to the core per KeenGamer and Steam guides). In Leon Must Die Forever he's the final boss of every run (see Extras).

Step by step

Phase 1, melee: single and double swipes, a 3-hit combo, a long-reach thrust, overhead slaps, backhands, lunging stabs, a crouching quick flick and a close-range kick. He side-dashes to dodge gunfire. Parry (L) and shoot.
After enough damage he kneels: melee prompt. Use the breather to break the arena crates (Rifle Ammo, Med Injectors).
Electric part: he leaps onto a platform or scrap pile and absorbs ARK's energy. You get about 10 seconds to unload (Game8: the Requiem goes here).
Then a glowing line runs along the floor towards you with tendrils striking along it: it only travels straight, so run sideways early. Next a circle glows under you and he lands a jump slam with a big AoE: sprint out and punish the landing with the Requiem. It can't be parried. A shoulder charge follows: parry or sidestep.
The trickiest move (mostly on Insanity): a jump with a tentacle dive-bomb followed by his body, which needs 2 quick parries in a row (VGC). Each cycle gets faster; late on he laughs and flails the tentacle in every direction: many parries in a row.
RPG-7: he pulls out an RPG-7. Shoot him quickly so he drops it, pick it up (make room in the case) and fire it at him. There's only 1 rocket: don't miss. That ends phase 1.
Phase 2: pop the 3 red pustules (head and each arm or shoulder) with the SMG (Game8: the fastest) or the rifle; TheGamer does the side ones first. Sidestep back and forth past his single-arm, alternating, two-arm overhead and outward-moving slams, or parry: everything can be parried. He has a grab: stay out of reach.
With the 3 pustules gone he slumps: a cluster of pustules at his base appears. A Stacked Hand Grenade in the middle of the cluster usually clears it (IGN); otherwise one bullet each.
Second cycle: 5 pustules on the head and upper arms. Face first; wait for the arms to drop before sniping the arm ones. Another floor cluster: grenade.
Final grab (scripted): mash to break free and complete the last button sequence. Leon finishes him.