If he is crazy? Then let called it Undertale: the craziest breath ( logically all stack au/timeline/no-au can be sad,crazy,power,guilt,determination,coded,monster )
Well if there's LB!FTT with losing their own mind, it would be: Former Time Trio: Fallen Sanity Undertale Crazy Potion (drink some mysterious potion???) Dusttale Last Insanity (become a cold blooded psychopath after seeing the TRUTH) Undertale Last Injection (From injecting 10% of DT on himself like the Doctor said in phase 1 to all of them in phase 2)