Grey Fullbuster

when Grey Fullbuster or a guild wizard enters the battlefield add 3 nano counters to Grey Fullbuster
Remove 3 nano counters deal 3 damage and {t} target creature
{t}Remove X nano counters exile target permeant
with mana value equal to or less than X,
and destroy Grey Fullbuster
{t}Remove 6 nano counter sacrifice Grey Fullbuster
add Grey Fullbuster(Demon slayer) to the battlefield.