It seems the No EXP Medal is also preventing loss of EXP.
I have only tested it on my Lv.1 character, he has 36 EXP, and I can't lose it.
EDIT: I'm not losing EXP at all when I die at Lv.1... I don't want to level up >.>
Edited by Banrukai, 18 January 2016 - 11:54 PM.
