you and Sonic were enemies, Sonic decided to ask shadow to be a spy to find out what you think about Sonic, so he has to stay with you, (you didn't know anything about Sonic's plan), Shadow had to be a spy, he hoped that I wasn't caught by you. So one day you and he met, you were still cold and serious. after a few days he was starting to have feelings for you, but he was still serious and cold (he didn't show it).