Easterling Rider

First strike (This creature deals combat damage
before creatures without first strike.)
Flanking (Whenever a creature without flanking
blocks this creature, the blocking creature gets -1/-1
until end of turn.)
Unleash (You may have this creature enter the
battlefield with a +1/+1 counter on it. It can't block
as long as it has a +1/+1 counter on it.)