The Iron Sentinels

Armored (Prevent the first damage of any source
of damage on this creature.)
Legion 3 (When this creature come into play, put
3 +1/+1 counter on it. For each damage dealt to this creature, you must prevent that damage by removing
one +1/+1 counter.)
{t}: Add a +1/+1 counter on this creature, can
only be used if the number of +1/+1 counter is
less than its Legion value.