Master Yi - Unstoppable

[LEVEL 3] I cost 2 and 1 Calm less. (While you have 3+ XP, get the effect.)
[LEVEL 6] I cost 4 and 2 Calm less instead.
[LEVEL 11] I cost 6 and 3 Calm less instead.
[LEVEL 16] I can't be chosen by enemy spells and abilities.