They're both giant robots, and therefore mecha; and are robot sisters(which I'm not going to explain because explaining familial relations between robots is insanity inducing).
Fenir said: They're both giant robots, and therefore mecha; and are robot sisters(which I'm not going to explain because explaining familial relations between robots is insanity inducing).
They're simply two A.I.s developed off the same core program architecture, with related yet different personality coding. Surely that's less insanity-inducing than explaining why they have erect nipples sculpted into/protruding through their chest plating. (At least, it's more difficult to explain if Joel Schumacher isn't involved.)