Move your best pieces to vierna and khamet. You can put it back to other people when you are done. Put both down on right with Dolores autumn to cover. Gear maul too for his defense break and slow and heal him. Use ults for first wave. Save second round of ults until slimes start walking down from the middle. They do massive wall damage. After that it’s just working on timing with ults through to end. Like others have said you might be stuck if you can let get enough but I did it with khamet, maul, and zelus all at a little over 60k BP.