He could have colour changing abilities, which fits in nicely with his bio and camaflague concept.
He could be painted with paint that changes from blue to purple in heat, and therefore could have both colour schemes (blue+purple->all purple)
This also adds a extra exciting feature to the potential MOTUC figure, which, let's be honest, would be a bit bland without it!
(Also, in the UK /German comics, I got the feeling that the writers got him mixed up with Vizar (he had telepathic powers, yes?), and so the artist just drew Nocturna due to this mix-up.)