Responses
In the novel they are blood related. It’s just for I’m guessing censorship reason the manhwa changed up the novel story to where the mc was born from the mothers friend(?) and raised the child with the younger brother to make it seem like they are twins when in reality in the novel the mc is blood related twins with Tibain and younger brother to Logan

I know they are blood related I just can't prove it... Took me a while to realise