Hades grants this God Power that causes 4 stony guardians to rise from the ground and protect a Town Center belonging to you or an ally. 

To summon the Sentinels, left click on the Sentinel icon at the top of the screen, then left click on a Town Center. If there is not space for all 4 Sentinel statues, some may appear red. You may use the God Power anyway and create fewer statues, or you can try to remove the obstructions (such as deleting a building), or just use the power on a different Town Center.

The Sentinels are affected by improvements that make buildings stronger.