Champion of the Freljord- Arnor: Ward of the Citadel

I don't do this often, just something I do for "fun" every once in awhile. Below is a concept of a champion hailing from the frost-bitten lands of the Freljord. Enjoy/critique/or anything in between as you wish.

Passive (two parts): Frost Bite:

1. Arnor thrusts his tusks forward a short distance dealing % of his max health as magic dmg. If this kills the unit, passive is refreshed. (20s/18s/16s) Works as an empowered AA.
2. Spells and AA's "mark" target (this applies to jungle creatures as well) After 4 marks, the next spell or AA will consume the mark dealing % of his max health as magic dmg and slowing the target.

Q: Ferocious Charge: Arnor lowers his tusks and stampedes for a duration of up to 3s (can be recast early to stop) all enemy units in his path. Arnor is able to change directions of his stampeding path similar to how Nunu changes direction with his snowball and becomes "unstoppable during the charge. Arnor gains movement speed over the duration. Additionally, if Arnor comes in contact with an enemy champion, they are scooped up onto his tusks and tossed up into the air at the end of the duration or if recasted early. Upon landing, enemy is slowed. If champion comes in contact with terrain, they are stunned and take an additional mark. deals % magic dmg.

W: Thick Hide/Rampage: Passive- converts % of armor into health.
Active- Arnor's next 3 AA's deal % of his max health as magic dmg, have increased attack speed and slow the target.

E: Thundering Impact: After being in combat for 5s this ability can then be cast (similar to volibear's "W"). Arnor leaps forward a short distance (like illaoi "W") and slams his hammer into the ground stunning all enemy units at the center and sending out a shockwave that dmgs and slows other enemy units caught in the blast. Deals % magic dmg.

R: Freljord's Might: Arnor raises his hammer high, after a brief delay, he strikes the ground with great force sending out a shockwave that deals % magic dmg and errupts an arena of ice around the perimeter of the effect (about the size of Trundle's 'W'). Inside this arena Arnor gains a % of his Armor/Max health/ and a flat amount of attack speed.

The Idea for this champion is a bruiser/tanky fighter from the Freljord. I'd like him to have a Mammoth feel to him.

Let me know what you think!