Vilis, broker of life and card draw (EDH / Commander)

The goal of the deck is to pay life and draw cards. Many possible wincons available:
Big mana with Skrige Familiar then Exsanguinate or Torment of Hailfire.
Repay in Kind enables a faster win by bringing down my opponents to my low life total. It could also draw tons if cards if I'm somehow not at the lowest. Repay in Kind can also kill my opponents by targetting them with Sign in Blood, or any other "target player draw cards and lose life".

There are also some loops to draw your whole deck then reshuffle it by discarding Kozilek Butcher of Truth:
Mindslaver an opponent and draw it back once you have reshuffled your deck back into the library, same with Blood Tithe or with Praetor's Grasp.
All the loops need Vilis, Skirge Familiar, and Elixir of Immortality or Kozilek in order to cast spells and draw them back. They all work very similar to the loops you can also find in Gitrog Monster decks.

Platinum Emperion may look like a nonbo but it help survive if the pressure on your life total becomes too important, but where it shines is with Ad Nauseam, "draw" your entire deck and lose 0 life.

Blood Celebrant will draw half of the deck "pay B, pay 1 life (trigger vilis), make B, repeat" and he also helps casting stuff you've got with Praetor grasp.

Special mention with Necropotence: each time you activate it, you can hold priority and activate it again, while letting Vilis triggered ability resolving inbetween. The discarded cards will trigger Necropotence, that means if you've discarded Kozilek, you can shuffle your graveyard into your library before Necropotence's ability resolved.

Anti graveyard hate are either Elixir of Immortality, which can be looped too to gain some life back, or Entomb Kozilek in response to the hate.