Mr. Pheffer is the manifestation of Toasty's emotionally repressed psyche, therefore he is only visible to Toasty. Although Mr Pheffer "sacrificed" himself to save Toasty from Sekushi, he reappeared to guide Toasty as he fought in Duel Revolution. When Toasty revealed his suprise at Mr Pheffer's reappearance, Mr Pheffer merely stated that since he was a manifestation of Toasty's psyche, he could do "whatever the #@$!" he wants (meaning that since it's all inside Toasty's head, he can reappear when he wants). His main goal seems to be to use Toasty to gain control of the world.