Video: Grim Dawn. Олехра+Игнаффар VS 200 Шард(максимальный скейл боссов) Архимаг Александр. - YouTube
GT link: Mage Hunter, Level 100 (GD 1.1.9.6) - Grim Dawn Build Calculator
As long as the bosses on stage can all be frozen (only few bosses with over 150% freeze resist cannot be frozen forever), it’s not hard to pass the boss room.
And the first 3 rooms? Pull monsters carefully and do the same thing as if in the boss room. No big deal. Just take longer time.
Thanks for your excellent work. @AlexGoldFish_322