Nero, Lord of Inkheart

Counters can't be placed on Nero, Lord of
Inkheart.
Whenever Nero, lord of Inkheart or another
inkling enters the battlefield, you may place -1/-1 counter on target creature you control.
Remove any number of -1/-1 counters from creatures you control: destroy all nonland
permanents with mana value less than or equal to
half the number of -1/-1 counters removed
rounded down.