Lucius the Eternal

Double Strike
Lucius the Eternal enters the battlefield with {x} +1/+1 counters on it.
When Lucius the Eternal deals damage to a creature put a +1/+1 counter on it.
If damage would be dealt to Lucius the Eternal, prevent that damage and remove that many +1/+1 counters from it.
Whenever a +1/+1 counter is removed from Lucius the Eternal, put two +1/+1 counters on it at the beginning of the next end step.
{t}{r}{r}{r} Emperor's Children Marines you control gain Double Strike.