When Viscera Seer dies, Mortuary and Fleshtaker trigger.
Resolve the Mortuary trigger, putting Viscera Seer from your graveyard onto the top of your library.
Resolve the Fleshtaker trigger, causing you to gain 1 life and scry 1.
Resolve the Viscera Seer ability.
Cast Viscera Seer from the top of your library by paying 1 life.
Repeat.
This clever loop turns your library into a recursive engine by leveraging Mortuary, which automatically recycles any creature that dies straight back to the top of your deck. Viscera Seer acts as the sacrificial outlet to feed the graveyard, while Fleshtaker rewards every single sacrifice with life and filtering. Because Gwenom, Remorseless allows you to cast spells directly from the top of your library by paying life instead of mana, you can bypass traditional casting costs to continuously replay the sacrificed Viscera Seer over and over again.