Kharn, 8th Assault Captain

Haste, first strike
This creature must attack each turn if able unless
you pay {b}{r} and you tap it
Butcher's Nails: whenever you attack with all the creatures you control, this creature
gets +3/+1, menace, double strike and trample until end of turn
{2}{b}{r}: attacking creatures you control get +3/+1, menace, double strike, hexproof and trample until
end of turn. They do not untap during your next untap
step unless you pay an additional {1}{b}{r}