Ryu, Trampling Sensei

Whenever a creature or planeswalker an
opponent controls is dealt excess damage, add
mana of any color to your mana pool for each
excess damage.
Creatures you control with trample have +1/+1.
First Strike, Trample,
Trample over planeswalkers (This creature can
deal excess combat damage to the controller of the planeswalker it's attacking.)