MTG Salvation

Kind of. For your reference: http://yugioh.wikia.com/wiki/Slifer_the_Sky_Dragon

I find Osiris to be a very interesting card and I want to create a deck modeling after its power.

Osiris has power and toughness equal to the number of cards in controller's hand, much akin to our beloved Maro. In addition, any creature summon by your opponents would automatically lose a fraction of their power and toughness, which could potentially destroy them outright. Last but not least, Osiris is a God card, which means it cannot be affected by most spells or effect, and those that gets through last only one turn.

So combining above attributes, here is a rough list of card choices of the Osiris deck, with ideas borrowed from the original user of such deck, Marik Ishtar:

Multani, Maro-Sorcerer = Immune to targeted effects and size depends on cards in hand.
Æther Flash + Everlasting Torment = Permanent damage (or death) to creatures when they enter battlefield.
Reliquary Tower = Infinite hand size.
Harvester of Souls + Reassembling Skeleton = Card draw base on dying/returning creature. (Skullclamp is powerful but unfortunately doesn't work well with Aether Flash)

Any suggestion to make this deck even more viable? Heartmender or Quillspike to remove -1/-1 counters from Multani if he ever gets it?