Valorne, Honored Guardsman

Defender
Creatures with power equal to Valorne's power can't attack you or planeswalkers you control.
Valorne enters the battlefield with one bravery counter on it. Whenever a creature enters the battlefield under an opponent's control, you may remove a bravery counter from Valorne. If you do, Valorne gets +X/+0 where X is that creature's power.