@Gakuku I'm actually fairly sure his support of Greed is recent. We see him scheming to mess with Kaiser Fritani earlier (the part where the other dragons were whispering to each other about how Kaiser is at it again with his overprotective love for his granddaughter). I'm betting THAT'S when he infiltrated the tower and supported Greed. He might not have realized how bad it was. He was basically giving Greed items through his statue. So while he supported a major villain, he might not have known just how bad he really was, or perhaps didn't know at all that he WAS a villain.