Basically SoH Sisters with a HP check.
Strat -
HP on both nameds must be decreased in Balance.
5% Threshold works fine.
Both will periodically call for the tank archetype they need to be tanking them. (Brawler/Warrior/Crusader). Must be on the right tank, or will one shot their target and keep one shotting targets till they find the right type.
Nothing more to fight. Keep them balanced, and on the right tank archetype.