High Queen Khalida

Vigilance, Wither (This Creature deals damage to Creatures in the form of -1/-1 Counters.)

Venom Staff - {w}{w}: During your Main Phase, you
can Remove any number of -1/-1 Counters from
Creatures your Opponent controls and gain that
much Life.

Constructs and Cavalry Creatures you control gain
+1/+1 and Haste.