Here's my
Almighty Raisin page at Oddworldian.
I don't really know any other details about it on top of what has already been said. I just think Raisin is a pretty cool character. He's (is that the right pronoun?) like a tree, with textured skin and roots coming out of its' body.
I imagine Raisin's voice as being loud, deep and hollow sounding. A giant raisin. I wonder if the Glukkons have ever tried to chop him up for a delicious raisin snack product?