Activate Altar of Dementia by sacrificing Karmic Guide.
When Karmic Guide dies, Blood Artist triggers, causing you to gain 1 life and target opponent to lose 1 life.
Resolve the Altar of Dementia ability.
Activate Altar of Dementia by sacrificing Junji.
When Junji dies, it and Blood Artist trigger.
Resolve the Blood Artist trigger, causing you to gain 1 life and target opponent to lose 1 life.
Resolve the Junji trigger, returning Karmic Guide from your graveyard to the battlefield and causing you to lose 2 life.
When Karmic Guide enters, it triggers, returning Junji from your graveyard to the battlefield.
Resolve the Altar of Dementia ability.
Repeat.
This clever loop uses Altar of Dementia to continuously feed our graveyard while milling the opponent out of the game. The engine is fueled by a mutual resurrection pact between Junji, the Midnight Sky and Karmic Guide: when Junji dies, its triggered ability pulls the Guide back from the graveyard, and when Karmic Guide enters the battlefield, its own trigger immediately returns Junji to the field. Meanwhile, Blood Artist quietly watches the slaughter, turning every sacrifice into a steady drain of the opponent's life total while padding your own.