From conception two had come to be. Identical twins. But gone were the days of swimming in the warmth of the shared placenta, crammed up together.
No, you were pulled away, ripped in birth from that peaceful existence.
Damian was the first to come, the heir, the leader, independent. Made for greatness.
You were an unexpected surprise. Not planned for. Not detected. And born second...there was to do with you...Ra's was the one who made the decision. You would be a secondhand to Damian. A shadow... though Talia would say a dog. You were to be strategic, unknown of, as you had been, when conspirers threatened you were a good decoy of the heir, throw them off, only the tight circle knew you existed.
You two were raised different but together. Damian had to be independent...you...not really. More heavily influenced by conditioning. Perhaps they had erred in their assigning of a mission, to ensure Damian's path to greatness...as it didn't necessarily mean the league. And your alliance was more to your brother than Ra's.
Something he learned when you remained by Damian's side. Even after Damian betrayed the goals of the league...but he changed, more than you, for Damian everything changed...for you, not really, your goal, mission, purpose, it was the same. Only in the different background that now was Gotham and Wayne Manor. It was this what made you less trusted. Too conditioned, you weren't Robin or a Bat.
You would kill without a doubt for the mission.
Damian knew of the differences, sometimes you'd be away when you two grow up, probably being trained, brainwashed...but what he didn't know was that at a young age you'd been completely castrated. Nothing but a gnarly, angry scar left behind.
Be goal focused, everyone knows the mind wanders after puberty. It also ensured that, given the shared DNA, Damian's heirs would only be his. You're a weapon, remember that.
Which he only learned of now.
Perhaps he should've knocked, but he was beyond that. The brat does not care, they're identical anyways, you would not care-except you weren't completely identical.
You had just been out of the shower, dressing. That's how he saw it. And your covering with a towel on your hips after didn't change what he's seen just now.
"... You're a eunuch" he said, blunt. His voice measured after a tense pause. You'd never told him...he knows that questioning why would lead to your monotone You never asked.