Start by casting Raining Fire on a group of three enemies. Then immediately cast Noxious Fumes where the three enemy gods are standing. Note: To make this easier, have a ground targeter set up as part of your targeting system and have Noxious Fumes on Quick/Instant Cast. Because your targeter is already on the group of enemies for Raining Fire, Noxious Fumes will land in the same location and cause a stun. This may require a few attempts before the enemies end up grouped correctly. Have Agni unlocked and in Assault will make this easy.