Okay I bought the whole using his arm to perfect viability of Cadmus' human cloning, it made sense, I mean cloning is hard (and messy ;P ), for it to require that much tissue, fair enough, but reading Roy's page noticed something that could suggest something a little more sinister, also explaining why Roy was targeted as a clone over other sidekicks or heroes, an additional reason for his behavior in Satisfaction at the end (which I also considered to be fair under the circumstances.)
In the comics, Roy and Lian through him were far descendants of Vandal Savage, and because of that targeted him as a source of organ transplants to keep him alive (or fresh/? since he can't die), I'd imagine that centuries of equisite wines and liquor would do massive damage to any liver or kidneys, and the cholesterole, phoo, but Why use him once when you can clone an array of spare parts?
This Was asked to greg if they're related, of course the answer was SPOILER REQUEST: NO COMMENT, this is anything but verification, I'm just saying it so that you don't ask him if this is the case. He. will. not. answer. you..