I've actually heard from a few different anonymous sources - who were reliable enough to tip me off to the events of "Dark Reign" months before the first rumors started coming out about that - that Loeb originally intended Rulk to be "Thunderbolt" Ross, but as soon as fans guessed that's who he was, Loeb threw out those scripts. Now, according to those anons, not even Loeb knows who Rulk is anymore, nor is he even bothering to figure it out anymore.