Melira, Sylvok Outcast

You can’t get poison counters.
Creatures you control can’t have -1/-1 counters put on them.
Creatures your opponents control lose infect.

Lost Leonin

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Chancellor of the Annex

You may reveal this card from your opening hand. If you do, when each opponent casts their first spell of the game, counter that spell unless that player pays .
Flying
Whenever an opponent casts a spell, counter it unless that player pays .

Shrine of Limitless Power

At the beginning of your upkeep or whenever you cast a black spell, put a charge counter on Shrine of Limitless Power.
, , Sacrifice Shrine of Limitless Power: Target player discards a card for each charge counter on Shrine of Limitless Power.