Is this inspired by Path of Exile? The only MMORPG that had permadeath that I can think of is Shaiya, even to this day they have "normal" and "ultimate" mode (previously had also easy mode) which affects the amount of stat points you get per level (5 vs 7 respectively). In order to preserve your character, you had to buy a special cash shop only item that would be consumed upon your death, but you'd keep your character, then they added a 15-day and 30-day buff later. Game ended up being p2w so hard, it just collapsed on itself.