Dokubi, Emerald Nightmare

Flying, supremacy 2 (Whenever a creature dealt
damage by this creature turn dies, put two +1/+1
counters on this creature.)
Whenever a Dragon you control attacks, Add {b}{g}. Until end of turn, this mana doesn't empty
from your mana pool as steps and phases end.
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"It ruthlessly stalks my people. Knowing it's always
there is almost worse than it actually striking.Almost."-Alesha, Who Smiles at Death