First of all, I made these changes to fit her better into her theme (remember, she is getting a VU soon)

English may not be 100% correct. Hope you guys like it  :) (my first post, be pacient)

Passive: When out of combat for 5 seconds, Evelynn turns stealth, only being seen by nearby enemies or true sight. 3 seconds after exiting stealth, Evelynn's next basic attack or basic ability gains a bonus effect.  

- Basic attack bonus: Evelynn's next basic attack summons spikes around her, dealing damage and healing her based on her missing health

Q: Evelynn unleashes a dark flame in a line, stopping at the first enemy hit, dealing damage over time. If the target stays near Evelynn while taking damage, it'll be feared after a few seconds.

- Passive bonus: Instant fear and damage.

W: Evelynn gains bonus movement and attack speed for a short duration. Spell hits reduce the cooldown of the ability by 1 second. Kills and assists reset it's cooldown.

- Passive bonus: Double movement and attack speed.

      Note: Has now a small mana cost and no longer removes slows.

E: Evelynn strikes her target twice, dealing damage and applying on-hit effects and reducing it's magic resist for a few seconds.

- Passive bonus: Evelynn fires a line of spikes through the target, dealing the same damage and healing as much as basic attack spikes.

R: Evelynn damages all enemies in a area, dealing base damage plus a % of their current health, slowing them briefly and granting her a small shield for 1,5 seconds. If Evelynn is within the area, she will become stealth for 3 seconds, but W will enter in a brief cooldown. Kills after the first stealth will stealth her after 0,75 seconds, but reducing its duration by 1 second for each stealth after the first.      

    Note¹: This ability's stealth is different from her passive's stealth      

    Note²: Evelynn is granted 10% increased size for each enemy she hits (just for fun)

Good with: Gnar, Morgana, Nami

Bad against: Kalista, Janna, Lee Sin

I really hope you guys liked it. Feel free to give your opinions about Evelynn, the Voiceless Scream (nickname I've just created) :)