They were cleaving fast across level 22. The hard light constructs Sariel launched that imploded on impact were a spell Damian had never thought possible. But Sariel was doing it, along with another spell that created abyssal voids of darkness—gateways to who knows what dimension—allowing dozens of black hands to emerge from the ground, grasping their opponents and holding them in place for free attacks.
It worked somewhat similarly to his vines, but these were much more powerful and harder to escape from. Only light spells were effective against them, and monsters, of course, could do nothing at all. Sariel could only create them wide enough for barely half a hand's length, but even so, they were incredibly useful for slowing down enemies.
Damian, naturally, stole the guy's spells without any shame. He just made sure not to perform them in front of him for now.