Well... there was no "training" done or use of the original art, it was just a different interpretation of the character done with AI assisted tools for one of his Fans. You don't need consent to use a character in a transformative way of Fanart. I hope R3dspike doesn't mind tho.
No, they literally requested Me to do it hehe... I used AI Assisted tools ;) the AI doesn't do stuff by itself. This is a bigger conversation to be had. I take it that you don't like AI... thats alright, to each their own :D