Activate Altar of Dementia by sacrificing another creature.
When the creature dies, Bishop of Wings' second ability triggers, creating a 1/1 Spirit creature token.
When the Spirit token enters the battlefield as an Angel due to Arcane Adaptation, Bishop of Wings' first ability triggers, causing you to gain 4 life.
Resolve the Altar of Dementia ability.
Repeat.
This clever loop transforms a humble flock of spirits into an unstoppable engine by leveraging the passive enchantment Arcane Adaptation to rewrite reality, ensuring every creature token you control counts as an Angel. With those type-shifted tokens arriving in droves, Bishop of Wings immediately rewards you with a burst of life upon entry and automatically replaces every fallen comrade with a fresh 1/1 Spirit whenever one leaves us. That seamless cycle feeds directly into Altar of Dementia, letting you endlessly sacrifice those replacement tokens to mill away your opponents' entire libraries while keeping the loop spinning indefinitely.