Akai community-reported

Kill achievement: CHAINBREAKER unconfirmed

A late-game boss players consistently name in help threads — the current "cannot beat" hot spot is his second phase, which players call "way too fast" and say barely leaves room to heal. The Akai Chainbound blade named in launch reviews, and the CHAINBREAKER achievement, both plausibly tie to this fight — neither link is confirmed yet.

Strategy

Players who cleared phase two recommend: put roughly 70/30 of your stat points into attack/health, use a greatsword (critical hits on every deflect), and save a freezing summon to stun him for a full light-light-light → heavy-heavy punish window. community-reported

Source: Steam discussion 'Cannot beat boss' — strategies aggregated from the replies

A summon that heals you on parry is repeatedly recommended for this fight, and watch his reach on every third or fourth attack — that is the string players say catches them. community-reported

Source: Steam discussion 'Cannot beat boss' replies; an 'Akai bug' thread also exists — see the bugs page

Core mechanics that matter here

Deflect / parry — timed blocks that build the boss’s Resolve Bar. ✓ corroborated
Instinct Counter — the heavy counterattack available when the Resolve Bar is full after perfect parries. ✓ corroborated
Soul Arts & Boss SP — upgrades bought with SP earned from bosses; the Meteor Slice / Dash / Zone lines each have max-upgrade achievements. ✓ Steam-verified
Ghost Summons — defeated bosses can be unlocked as summons with passive perks. ✓ corroborated

Found something wrong, or beat this fight with a different setup? Send it in — corrections ship same-day and reports are credited.