The darkin slayer

Lore:Noxian retired mercenary caught the news of the slow return of the darkin. Knowning danger of their existence the darkin slayer steps out of the retirement and sets off to find the remaining darkins and seal them for good.

The darkins are known to be immortal but the slayer has a way to defeat them. 'fight fire with fire'. The darkin slayer is able to wield a weapon of millenia without any issue and can utilize its power to his own will. The darkin within is still alive and wants to take control, yet for some reason can't fight back. Although the slayer is able to dominate the darkin, the wielder is still mortal, also the slayer hasn't changed appearancewise.

As for the darkin... I thought the old sword of aatrox would be fitting, but change my mind if you have something better.

Note that this is just an idea of mine but feel free to voice yours what the slayer could have been and what he is capable of instead. (since I know for the fact that the community has better ideas than this)