Toketsu, Brother of Ice

If a source an opponent controls would deal
damage to you or a blue or black permanent you
control, prevent 1 of that damage.
{3}{u/b}, {t}: Target attacking or blocking creature
gets -2/-0 until end of turn. Then if its power is
0 or less, untap Toketsu and exert that creature
unless its controller pays {2}.
Parter with Futto, Brother of Flame