Board Thread:Questions and Answers/@comment-13886763-20160426181210/@comment-24685938-20160501074721

Stryzzar wrote: Well even if that's the case, de-aging isn't instantaneous. You could de-age Diagon a few centuries and he'd still have more than enough power to kill Maltruant.

Actually amortal means something that can't be killed because they were never technically alive. While immortal means alive but can't die, it doesn't neccessarily mean they have to have been "born". He can stop time and de-age Diagon then. On the superpower wiki it stated that

"May be erased from history via the effects of  time-manipulating powers, killing the immortals in question  before they become immortal."