When Mogg Fanatic dies, Mortuary and Blood Artist trigger.
Resolve the Mortuary trigger, putting Mogg Fanatic from your graveyard onto the top of your library.
Resolve the Blood Artist trigger, causing you to gain 1 life and target opponent to lose 1 life.
Resolve the Mogg Fanatic ability.
Cast Mogg Fanatic from the top of your library by paying 1 life.
Repeat.
This clever loop relies on Mortuary to intercept Mogg Fanatic the moment it hits the graveyard, neatly tucking it back onto the top of your library instead of letting it rest. Meanwhile, Gwenom, Remorseless provides the vital permission needed to recast Mogg Fanatic straight from the top of your library, trading life instead of mana for its cost. Because Mogg Fanatic can sacrifice itself for damage, you can continually recycle it to fuel Blood Artist, draining your opponents' life totals while easily absorbing the life payment required to keep casting.