Sakonmaru Oni, the Pursuer

Bushido 4 (Whenever this creature blocks or
becomes blocked, it gets +4/+4 until end of turn.)
Vigilance, first strike
Before each of your combat phase, choose a
planeswalker. If Sakonmaru Oni attacks that
planeswalker, it gets +1/+1 and gains hexproof
until end of turn.