Rockwell was a scientist and he found element 103 he injected other survivors with it and they turn into nameless and soon he was so obsessed than evryone in the town got injected but the survivors that left

He injected the element into himself causing him to to turn into this monster in aberration when genesis part 1 when you defeat his the master corrupted controller (a servant of Rockwell) Rockwell gets in a rage and takes you down in his ship that’s he is in control at this point Rockwell’s appearance changes from monster to a tiny bit human a tiny bit but still mostly monster