Rending shade bugs
Aegis isn’t the most important thing to steal imo.
Protection, resistance, quickness, fury, regeneration, vigor. These are highly beneficial to you in a fight and losing them, for your enemy, is equally problematic. Aegis only protects them from one auto-attack.
It turns a class with relatively low boon access, especially defensive boons, and gives us matching access to whatever we are fighting.
or you could just simply backstab a guardian, because other classes aint really getting aegis