Graybeard Jax
Now I'm not an artist nor am I creative but a graybeard jax would be cool. Imagine it
The skin generally sticks to the default skin. For the most part. So his whole cloak Will be darkish gray. It'll be less bulky but his body outfit would be lighter gray. So his cloak will be darker than his body His cloak will also be burned, torn, dirty etc. it'll look worn His skin will be a faded purple with a hint of gray in it to show that jax is and old man His eyes will be glowing yellow in the darkness of his hood and a simple long gray beard will hang from the darkness of it
Now his weapon: His weapon will be a staff with a purple shiny gem on the top. The gem is purple because it's infused with the essence/power of his youth. Which makes the staff much stronger so and old man jax will have the strength and energy of young jax. His Q would be the same thing but when he jumps down there's a little flash of purple smoke. His W will make the gem shine bright and make his weapon glow purple with the essence Which is making the weapon even stronger with his youth. Which is why it costs mana His E will be the Same but when it spins above his head it'll be a purple swirl instead of just normal white His R will give him the armor/magic resist buff like usual but he'll have a purple essence coming off of him which gives him the energy and strength of young jax allowing him to resist the damage. His passive will make the gem glow brighter with each stack giving him the energy of his youth making him swing faster.
I know it doesn't sound the best and I don't have a picture but I trust if this concept makes it into the mind of anybody they will have the image I have in my head and possible be able to draw it.