Complex sentence: Not much is known about the background of most Rayman-characters, not to mention, absolutely nothing sure about the characters, except for Globox, of who is known he has a wife called Uglette, and a few hundred kids.
Split into simpler sentences: Not much is known about the background of most Rayman-characters. Not to mention absolutely nothing is known about the characters, except for Globox, of who is known he has a wife called Uglette, and a few hundred kids.