This intricate loop hinges on Mortuary quietly routing any creature that dies straight to the top of your library instead of the graveyard. While Ashes of the Abhorrent sits on the battlefield quietly gaining you life whenever a creature dies, its primary role here is simply to allow the sequence without disruption—or rather, the life it gains offsets the cost of playing through your library. You sacrifice Wild Cantor for mana, triggering Mortuary to stack it away and Ashes of the Abhorrent to buffer your life total. From there, Gwenom, Remorseless enables you to cast that very same Wild Cantor straight from the top of your library, paying life instead of its mana cost, which is easily sustained by the life you're gaining along the way.