Thinking about creating my own mod skin - is it legal/will it be taken down if i show it off?

Tl;dr: I want to create a custom model to be used as a modded, client-side skin. What steps do i have to keep in mind to make sure it is completely safe to use, in other words not harmful to the game OR the user?

As stated in the title, i've recently been feeling like i want to create a modded champion model (as a skin only, obviously) as a reference to a certain anime.

The reason i'm asking is this: if i went through the effort and work of creating a custom model, texturing it and compiling it into a format usable but not harmful for the game, would i be allowed to show it off here on the boards? And most importantly; what steps can be taken to avoid it being "harmful" to the user? (As in, obviously, to avoid the skin being deemed as giving advantages to the user, and thus becoming a potential ban reason to those using it?)

Could either an actual developer or perhaps a techie give some insight?

My inspiration in question is "Silver Crow" from "Accel World" as a skin for Aatrox.

Referrences: http://p1.i.ntere.st/fbe395bc37a2e020fb557668b56fcb59_480.jpg

https://i.ytimg.com/vi/8cGib7cOS6g/maxresdefault.jpg

https://s-media-cache-ak0.pinimg.com/736x/df/51/2e/df512e2559a46015e91bb4c6a4544295.jpg

I wouldnt want to go through all the work of creating the skin if it'll just be deemed too dangerous to be used.

I already have both the knowledge required to make the skin AND animations for this. Pretty ambitious, which is why i'm terrified of getting started just to be shut down.

Thank you for your time.