Darth Vader Kassadin?... Come on RIOT i know you want my RPs <3 \(^o^)/
Like the Chosen One Master Yi skin, his W would fit the changing light saber color theme. The Q could be some kind of lightning extending outwards to the target and around him for the shield (I know Darth Vader doesn't use Sith lightning but it would look so sexy). The E would be a force push with small tendrils of dark side power waving in and out and sticking to the targets. His ultimate would look like an hyper space tunnel and his baking animation would involve a star destroyer for sure. His outfit already kinda-looks like Darth Vader's... just make it darker and add a few buttons to the chest plate ;).
For the copy right issues just put on those mickey mouse hears (no just kidding PLEASE DON'T!). But... seriously, did Riot ever tried/had to negotiate reasonable copy rights for skin concepts? If not would it actually eventually become possible given the growing size of the company? Riot could make some kind of a huge event with Disney to release a skin along with each of the upcoming movies or something (we have an expression in French that more or less translate to "i'm talking through my hat" meaning i'm talking big about something I absolutely don't know but you know... just throwing out the idea).
Other "chosen one" concept... Chosen One Diana => matches the changing sword colour theme Storm Trooper Graves => I know it's got nothing to do with light sabers but COME ON! Chosen One Fiora => would riposte laser bolts back to that pesky Trooper Graves Obi One Yasuo => he he he Darth Maul Wukong => imagine the ultimate WITH A TWIN BLADED CRIMSON LIGHT SABER :O
I could continue but I need to calm myself I'm way too excited lawl. (I CAN'T HELP IT I JUST LOVE THIS GAME AND I LOVE RUNNING AROUND SLASHING THINGS WITH A LIGHTSABER (Chosen One Master Yi might not be complicated or expensive but its my favorite skin :P))
Much love to all and PEACE OUT!
P.S. it's my 1st post so please don't hate me if did something wrong :s P.P.S. i'm French Canadian so syntax errors of all sorts can happen :s sorry...