Suggested by Sonic Hellboy is reasonably tough. Think of him sort of Luke Cage level as he’s got superhuman strength and speed. His speed in particular is pretty solid and edges into super territory. (As opposed to superhuman) That being said, Captain Planet completely outranks him in all categories. He can fly extremely fast and is basically a budget Superman. Hellboy will have a hard time damaging him although he could probably use one of Planet’s many weaknesses against him. So long as the Captain ends the fight quickly it shouldn’t be an issue though. Captain Planet wins.