Cast Channel by paying {G}{G}.
Activate Phyrexian Altar by sacrificing Bleak Coven Vampires, adding {U}.
When Bleak Coven Vampires dies, Fool's Demise's first and second abilities trigger.
Resolve the first Fool's Demise trigger, returning Bleak Coven Vampires from your graveyard to the battlefield.
When Bleak Coven Vampires enters the battlefield, it triggers, causing you to gain 4 life and an opponent to lose 4 life.
Resolve the second Fool's Demise trigger, returning it from your graveyard to your hand.
Activate Channel four times by paying 4 life, adding {C}{C}{C}{C}.
Cast Fool's Demise by paying {4}{U}, attaching it to Bleak Coven Vampires.
Repeat from step 2.

Infinite death triggers

Infinite ETB

Infinite lifegain triggers

Infinite lifeloss

Infinite LTB

Infinite sacrifice triggers

Infinite storm count

Fool's Demise

Channel

Phyrexian Altar

Bleak Coven Vampires

Combos with "Bleak Coven Vampires"