It is revealed in the episode "Mixed Signals" that his name is Ceasar. He was once a researcher on the nanite project. When the nanite event happened, he was trapped and launched into space in his...
he is like a nanny(baby sitter) to Rex - He is also the one to find Rex under a pile of rubble with no memory of his past and alone. You can see what happened in the episode titled "Promises...