Shadow is gay. He was originally made to be a caregiver before he was reprogrammed, but his intended role as a caregiver reveals that he is fundamentally feminine. In every scene with Sonic, you can just tell he's interested. He's always trying to beat or one-up Sonic, but deep down he knows that Sonic represents everything he has lost after being traumatized by Maria's death. Sonic, to Shadow, represents hope, optimism, and joy, three things he has lost after Maria's death. Even though he has this dark and brooding persona publicly, deep down he knows he needs Sonic to fill the void left by Maria. Research also shows that we are attracted to people who look like ourselves, and who looks more like Shadow than Sonic?