SMITE

"As Nemesis steal away 500 protections using Divine Judgement during a single match."

Divine Judgement is Nemesis's ultimate ability. It is considered a debuff-type spell where you select an enemy god within range to use it on. It normally drains the enemy of a % of their max health, movement speed and their protection.

To get this achievement you need to focus on the protections. The protections are what tanks tend to stack so that they take less damage. This means that whenever you use this ability you should target the tanks. You might be able to get this naturally targeting just about anyone if the game goes long enough, but to play it on the safe side, target the tanks.

I think I got it after using it about 5 times on a Geb.