The one on the left is the Moondragon, from my comic Eclipse. As he represents the moon, the moon is behind him. Sense, of course, my comic is just one of many so if you're reading this you probably don't read Eclipse, so just know that the Moondragon represents the moon (duh) and his brother/nemesis is the Sundragon, who's good. He obviously represents the sun, as well as Light Magic while the Moondragon is Dark Magic. The pupil of the Moondragon's eye is also the moon.
The one on the right is Thezar. He's from my comic, 4Key. He's also the biggest villain. He's the one who organized The Black Key (enemy organization for those who don't know 'bout 4Key until now). Behind him is Emerald Core--the massive emerald that's at the center of the Earth in that comic. He doesn't represent it like the Moondragon represents the Moon, but reaching Emerald Core is the goal of his life, for MaGiCaL reasons.

Yeah so lol I just thought it'd be cool to mix villains of different stories. They're both smiling at each other like "heeheehee". They'd make great friends.
