What's it like having a multiverse twin? There's another Tony Stark in these parts, isn't there?

[Theo doesn't really know what else to ask - he wants to know more about Tony. Know if he's close to the same one he knew before. It'll start to settle in to Theo's head soon that this unnerving feeling of disappointment he's feeling is probably something Willem went through time after time in the first reincarnations, when Theo kept resetting without memory. He doesn't like having things in common with Willem. So he'll throw himself into his behavior loops to escape it.]

Is twin the right word? Maybe you aren't identical.