The Mindskinner

The Mindskinner can't be blocked.
If a source you control would deal damage to an opponent, prevent that damage and each opponent mills that many cards.

Hidetsugu and Kairi

Flying
When Hidetsugu and Kairi enters, draw three cards, then put two cards from your hand on top of your library in any order.
When Hidetsugu and Kairi dies, exile the top card of your library. Target opponent loses life equal to its mana value. If it's an instant or sorcery card, you may cast it without paying its mana cost.

Marrow-Gnawer

All Rats have fear.
{T}, Sacrifice a Rat: Create X 1/1 black Rat creature tokens, where X is the number of Rats you control.

Neriv, Heart of the Storm

Flying
If a creature you control that entered this turn would deal damage, it deals twice that much damage instead.

Ognis, the Dragon's Lash

Haste
Whenever a creature you control with haste attacks, create a tapped Treasure token.