Jurin, Leading the Charge 
Legendary Creature — Human Barbarian
Haste Jurin must be blocked if able. Whenever Jurin attacks, each creature you control attacking a player gets +1/+0 until end of turn for each creature that player controls.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyLEGALvintageLEGALcommanderLEGAL