[Skin Concept] Soulstealer Mordekaiser
No metal. Only souls.
Donned in armors with lot of gaping holes alike skulls. Mace with Thresh's lantern concept. Feeling of empty when looked at.
Passive - Shield is greenish cloudy ooze similar to souls. Each time he kills units they turns into soul being devoured by his mace.
Q - Mace use the souls it has captured as power amplifier. Each build up turns darker with density of souls. Once last hit is unleashed, large amountl of souls are sent upward with their torturous expression.
W - Souls used as hostage. Small hint of wailing noise.
E - Tugs souls away from foes hit, if units are killed, their souls are violently pulled.
R - Needless to say more, but the ghost are more greenish in hue, and the particles of the ulti effect are also green.
I'm surprised this skin hadn't happened.