Battlewise Aven 
Creature — Bird Soldier
Flying Threshold — As long as seven or more cards are in your graveyard, this creature gets +1/+1 and has first strike.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyLEGALvintageLEGALcommanderLEGAL