Kargen, the Incinerator
Had this idea stirring for a while but never thought of posting it, saw the community of concepts and thought oh hell why not. Thanks for reading I would love to hear all kinds of feedback and I will try to answer as many questions as I can. (I had some cruddy drawings to go along w/ the abilities but they're lost in a notebook somewhere)
Kargen The incinerator.
Melee. Tankyish Mage.
Passive: Kargen does not use mana instead he gathers heat while standing in his burning ground, gaining Searing Flesh at max heat, he can release this heat into his abilities to empower them. Heat quickly cools while out of combat.
Burning Ground: Kargen’s abilities leave pools of Burning ground that deal damage to enemies who stand in it, lasts (X) seconds. Kargen gains heat from the flames he stands in.
Ability #1: Kargen throws fire to the targeted area, setting it ablaze dealing moderate damage, leaves burning ground. Empowered: Kargen lobs a large flaming orb that deals greater damage in a larger area, leaves burning ground.
Ability #2: Kargen creates a violent swirl of flame around him dealing damage and initiating his Searing Flesh (When Maxxed) to empower his abilities. Empowered: Kargen pulses twice dealing small damage the first time and slowing enemies around him and moderate damage the second in a larger AOE, leaves burning ground.
Ability #3: Kargen infuses an allied champion with flame increasing movement speed and placing burning ground where they were when the spell was cast on them. Empowered: Kargen infuses an allied champion giving greater Movement Speed, Attack Speed, Basic attacks deal extra Magic Damage and an area of burning ground is left where the champ was when the spell was cast.
Ultimate: Kargen Channels (Immobilized for the channel) fire to a single point for 2 seconds, the area then violently ignites dealing heavy initial damage that stuns enemies in the middle for 2sec and leaves a huge area of Burning Ground. (The damage area would be a circle that nearly touches all 4 braziers in mid lane if cast in the middle, AKA: Very Large) CANNOT BE EMPOWERED
Empower Combos: Kargen's Empowerment would work a such: You have enough heat and wish to use your Searing Flesh in a combo, you may Q, then W to initiate the stacks, this would cause your abilities to change where the empowered are on a totally different cooldown set, so you may do this sequence: Q, W, Q(empowered)
Aesthetics: I always imagined him as a human or other humanoid race, pretty muscular, insane in the head and augmented his body with scattered metal for slight protection (such as bracers, back plates, chest plates, partial head covering, being that the metal is fused with his skin not just strapped on) with a scrappy robe over top. Weapons would be extensions of his heavy metal bracers that extend blades out to the side of his hands (Like 
blade but to the side of his hands, connected at the bracer) , this frees his hands for spells but allows him to violently swing his arms to slice. Gaining Searing Flesh would ignite his robe and super-heat his metal parts to visually show he is able to empower. (Just a rough idea...im no designer)
IF YOU MADE IT THIS FAR THANKS FOR TAKING THE TIME TO READ THIS!