Showcase: All Will Be One Step-and-Compleat Edition

{U}, {T}, Sacrifice a creature or enchantment: Counter target spell.

First strike, deathtouch Whenever a creature an opponent controls dies, you may return target artifact card from your graveyard to your hand.

First strike, protection from red and from white Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

You don't lose the game for having 0 or less life. As long as you have 0 or less life, all damage is dealt to you as though its source had infect. (Damage is dealt to you in the form of poison counters.)

Deathtouch As this creature enters, choose a creature type. Creatures of the chosen type your opponents control get -1/-1.

All Slivers have "At the beginning of your upkeep, this permanent deals 1 damage to you."

A deck can have any number of cards named Shadowborn Apostle. {B}, Sacrifice six creatures named Shadowborn Apostle: Search your library for a Demon creature card, put it onto the battlefield, then shuffle.

Whenever a Sliver deals combat damage to a creature, destroy that creature. It can't be regenerated.

All Sliver creatures have poisonous 1. (Whenever a Sliver deals combat damage to a player, that player gets a poison counter. A player with ten or more poison counters loses the game.)