Kelsien, the Plague

Partner with Yannik, Scavenging Sentinel (When this creature enters, target player may put Yannik into their hand from their library, then shuffle.) Menace Whenever another creature you control leaves the battlefield, if it had one or more counters on it, you draw a card and you lose 1 life.

Partner with Silvar, Devourer of the Free (When this creature enters, target player may put Silvar into their hand from their library, then shuffle.) At the beginning of your end step, if you attacked this turn, create a 1/1 white Human Soldier creature token.

Target opponent exiles the top X cards of their library. You may cast any number of spells with mana value X or less from among them without paying their mana costs.

Flying Whenever this creature deals combat damage to a player, you may destroy target artifact or enchantment that player controls.

T: Add C. 1UR, T: Draw a card, then discard a card.

When this enchantment enters, support 2. (Put a +1/+1 counter on each of up to two target creatures.) 1: Choose target creature with a counter on it. When that creature dies this turn, return that card to its owner's hand.

Partner with Trynn, Champion of Freedom (When this creature enters, target player may put Trynn into their hand from their library, then shuffle.) Menace Sacrifice a Human: Put a +1/+1 counter on Silvar. It gains indestructible until end of turn.

Flying, vigilance, trample As this creature enters, choose artifact, enchantment, instant, sorcery, or planeswalker. Players can't cast spells of the chosen type.