Devin Levin

In appearance, Devin was outwardly indistinguishable from a human. The same is true for Kevin and other Osmosians that are not fully mature (Osmosians live for hundreds of years and it is at least a century before an Osmosian is fully mature, they also grow small horns on their head[2]) and Devin lacks horns on his head (it's possible he has them, but they are hidden in his hair or Osmosians can breed before being fully mature).