[Champion Concept] Seven-headed Dragon King
Fire element attack range: 280 (ranged) Wind element attack range: 550 (ranged) Water element attack range: 385 (ranged)
~~ ~~
Passive: Elemental Trinity: your abilities cause you to change your basic attacks.
Fire element: your basic attacks burn hit enemies for 20/30/40/50/60/70 (+20% of AD) (+10% of AP) magic damage over 3 sec. Wind element: your basic attacks increase your attack speed by 5/6/7% for 2 sec stacking up to 10 times. Water element: hit all enemies nearby you main target for 40% of normal damage and apply on-hit effects for 40% of their normal power.
~~ ~~
Noxious Ash Breath [q] Burn enemies in a cone for 40/60/80/100/120 (+20% of AP) magic damage. In addition, hit enemies starts to burn for 100/130/160/190/220 (+50% of AP) magic damage over 10 sec. Your Fire element or Wind element augmented basic attacks refresh duration of this damage over time effect. Your Water element augmented basic attacks remove this damage over time effect. Change your current element into Fire element. Cooldown: 10 sec Mana cost: 40 +5% of your max mana Range: 350 Width: 300 Casting time: 0.3 sec
~~ ~~
Tornado Gust [w] Flap your winds making several (2 +1 per 6 levels) randomly moving tornadoes. These tornadoes will move into targeted direction, but with unpredictable patterns and bounce of the walls and structures. Each tornado deal 30/45/60/75/90 (+15% of AP) magic damage per 0.5 sec to enemies inside of it. Each tornado lasts up to 3 sec. Enemies taking damage form more than one tornado receive only 25% of damage from additional tornadoes. Each tornado lasts for 3 sec. Change your current element into Wind element. Cooldown: 12 sec Mana cost: 20 +8% of your max mana Max movement range of single tornado: 900 Inside range of single tornado: 100
~~ ~~
Aqua Breath [e] Shield yourself and nearby friendly champions from damage for 4 sec. Shield absorbs 70/110/150/190/230 (+40% of AP) damage (halved on other friendly champions). Change your current element into Water element. Cooldown: 10 sec Mana cost: 12% of your max mana Range: 400
~~ ~~
Elemental Quaternary [r] Take on an element of earth combining all positive effects of all three elements (basic attack range becomes as wind's element) from your passive for 6/7/8 sec. In addition, augment your other abilities while this ability lasts:
Noxious Ash Breath: blinds hit enemies for 1/1.5/2 sec. Tornado Gust: slows movement speed of damaged enemies by 10/20/30% for 1 sec. Aqua Breath: heals affected targets for 30/45/60% of shield value in health.
Cooldown: 90/80/70 sec Mana cost: 50 +15% of your max mana
~~ ~~ Build examples:
or her father? After all, she was raised with dragons, wasn't she?
really. The wind element passive has me a tad confused when you say that it stacks up to 10 times. Does that mean the length of the buff stacks or the attack speed? And judging from that, I assume the wind passive has a cooldown? If it does, you didn't write it down. Just a little clarification here would be appreciated. ^^ As for the water passive, a small AoE that reminds me of 
but not as OP. All in all, complicated, but manageable and not too powerful. I assume that he'll be going either mid or top lane, so he'll be switching elements a lot.
's W. I like how it bounces off of walls and structures, so someone could hide behind a turret to dodge it, but it also lets you be sneaky with it too. You could bounce it off a wall and hit an escaping enemy with an unexpected angle, for example. It's also good that you toned down damage from multiple tornadoes - good balancing move. I can't think of any good criticism for this ability, except maybe the max movement range might be too long? I don't know lol
. I worry that it conflicts a bit with the rest of his kit, which is primarily a damage-dealing sort, and that the shield might make it hard to kill him in lane (I will fully admit, however, that this is potentially bias I have against shields on damage dealers because of 
and 
) I also don't think that it needs to shield allies; it's nice to help your buddies, but when you're playing a rampaging dragon king, you want to feel like one, so having a spell that protects instead of hurts sort of feels a little out of place. Plus you're likely big enough to shield them with your body, so...lol If I were you, I'd replace the shield with a damaging ability based on water - perhaps some kind of AoE like his passive? That's just a suggestion, though.
he's not going to deal with escaping very well. On top of that, I feel like CC would be this guy's kryptonite - he can't hurt you if he's too busy being plowed into walls and knocked into the air. He's a bit bulkier than your standard mage too, judging from the item builds you suggested, but with 
a thing now, ADCs do have a means of taking him down. Also, I believe someone else noted that his % mana costs will probably greatly hinder him, especially early on. So mana regeneration is a must for him if he's going to put out all the damage he's capable of.