Sion's unique item Soulfurnace (WIP)

This idea is still a work in progress but i figured i could post what i have come up with so far

Item Soulfurnace The healthstacking passive gets moved to this item. It's his Soulfurnace. It works kind of like Viktors hexcore as he will start the game with it.

Whenever Sion kills or assists on killing something he gains Lifeforce. The furnace absorbs the soul and uses it to fuel Sion undead body.

But now also gains Lifeforce. He gets an equal amount of Lifeforce as health for killing things so that would be 2 for small creeps/minions and 10 for big creeps/minions/champions Like Gangplank can upgrade his cannon, Sion can upgrade his soulfurnace with this Lifeforce to increase soulfurnace stats. So Soulfurnace is a bit of a combination of Gangplanks krakens and Viktors hexcore.

Soulfurnace has several upgrades which can be purchased 3 times to stack the effect for X amount of Lifeforce. The soulfurnace can only have 3 unique upgrades at once so the Sion player will have to choose which ones he wants.

Soulfurnace starts with no stats and just the healthstacking passive, Once all upgrades are completed Sion instead of Lifeforce regenerates 1 or 5 % of missing health upon killing small creeps/minions or big ones & champions.

Upgrades will come later, i was thinking of 5 or 6 unique upgrades of which only 3 unique ones can be aquired each game. Upgrades will cost an increasing amount of Lifeforce something like 50/100/150 but this is ofcoarse subject to change.

Curious what people think of this idea and if you have any awesome ideas for some unique upgrades do post them, but when you do keep a couple things in mind. Soulfurnace takes up an item Slot. Soulfurnace is a part of Sions's body so the upgrades increase his base stats. Each unique upgrade can be purchased 3 times for stackign effects, think + 100 hp buy it 3 times to gain 300 hp for example.

Ok thats it. Looking forward to feedback.