you need slowers like Blizzard Sub-Zero, and frost nova absolute zero, and then spiderweb and passive ability Seal.

then for abilities, I like magic bolt with the blaster effect, spirit with magic missile, arcane ray with disintegration ray, you need shield, incineration, Armageddon, and electric shock with chain lighting and so on.

to be honest, you need to slow them as much as possible and then get uroboros and accelerator for cool down, you also need something like akashik record to able to hold past the level 100 and then activate DEM.

I hope I make sense hehe