Mordekaiser Realm of Death Ability Idea

Hello,

I have thought about making winning the death realm fight more rewarding by giving Mordekaiser some minor permanent rewards for defeating someone in his realm. Instead of Mordekaiser getting 10% of his target's stats after winning, he permanently gains 5% size increase and 1.5% maximum health for defeating someone IN his realm.This would make it feel like Mordekaiser is getting stronger after winning many battles within his realm. What do you guys think?

EDIT: Maybe some soul stacks that give permanent stats for every victory in death realm instead?