8-Ball

8-Ball was a close friend of Xeno's, being the one to offer him a spot in the gang, which soon lead to his almost demise. When he found the other near death, he was filled with guilt and ended up taking Xeno back home to care for him. Though it meant extra work for him, 8-Ball paid for most of his needed repairs and color change, but when everything was said and done; he left Xeno to lower his risk of being found again.
8-Ball continued to stay in the gang for a few more years before getting out. Over that time, he got into more trouble and got his paws dirtier than Xeno's. He suffered his fair share of damage, even gaining a broken voice box that he's fine not fixing. Other damages (including mental) made his emotions a bit skewed, being difficult to feel or express for the Zoid, though he tries his best for those that have stayed with him.
Though it doesn't weigh heavy on him anymore (because of broken emotions), 8-Ball regrets most of the things he's done, especially what happened to Xeno.