What's going on with rendering?

it's not the collider that's important, it's the $$anonymous$$eshRenderer. it must be active, the gameobject's layer needs to match one that's rendered by a camera and the material if transparent shouldn't have 0 alpha.

That's a very odd angle that character is at... have you done any vertex deformation to the mesh but not recalculated the bounding box perhaps, causing it to be culled incorrectly?