Archon is a Greek word that means "ruler" or "lord", frequently used as the title of a specific public office. - Wikipedia

Name: Gaia, the Arcon of Mana

Champion introduction:
Gaia is a combination between a mage, a support and a off-tank. Her abilities thrive on having high amount of mana while her ult relies on you having full mana when taking damage and still being able to dish out high damage when losing mana. Whether the player wants to or not, they will have to tank some damage. Besides her abilities relying on mana, she also get's AP bonuses from mana. She isn't forced to, but she is able to support allies even on a pure mana/AP carry build. Her playstile is very unique as she will often play a combined role of a AP carry, a support and a tank if required and very often an initiator.
I also imagine her to look something like this:

She should look similar to this,but a little bit younger (about 19, her lore explains it).
A very weak blue shine comes from her body, almost covering it, but not like the visual for Elixir of Brilliance, more like a feint blue cat-suit.
She should have a staff similar to the one on the picture but with a blue crystal on it's end instead of the globe.
She should also have a glow in her eyes (similar to the one that Draenei from WoW have).
Her clothes could be the same (not like the other champs are better, I'm just sayin').
Voidborn Gaia = Take a Mystique from X-Man and make her skin like Kassadin's sword (same for her staff).
Battlemage Gaia = Gaia with shiny armor similar to Leona's and instead of a staff she has a sword.

Support, mage, ranged (can also jungle or tank)
Health: 360 (+76)
Health regen: 5.2 (+0.55)
Mana: 260 (+80)
Mana regen: 4.4 (+8)
Attack damage: 48 + (3)
Armor: 17 (+3.3)
Magic resist: 20 (+ 1.2)
Attack range: 480
Movement speed: 305
Attack range: 550
Base attack speed: 0.65

She has a voice of an about 19 year old girl (even though she is well above 30).
Upon selection:
-I'm gonna lay back and just watch em die....Problem summoner?
-To battle.
-The heck with them.
-Here comes the damage.
-Bye, bye.
-Where are we going? I hope it's not in a cave.
-Is anyone even there.
-Glad I don't wear heels.
-(annoying voice) Are we there yet...Are we there yet....Areee weeee theeere yet?
-Hah,the joke's on you, I'm not even a real tank.
-Your shoe is untied...Alright it isn't, but you still fell to my spells *laughs*!
Joke: -Am I insane? Hmmmmm..,YES!
-My mouth feels a little bit dry.Get me some mana potions.

Background story:
In the School of Transcendentalism in Ionia there was a young mage that surpassed any other mage at her age, even Soraka herself wanted to take her in to be her mentor. She might have accepted it, if she only wasn't obsessed with mana, thus, she refused. Gaia wanted to know everything about mana: What mana is, where it comes from, how can someone use it and someone can't. She had searched all books she had at her disposal yet she found little answers. She decided to start a journey to the depths of an ancient cave, located deep within the forests of Ionia, expecting to find ancient tomes that might give her some answers. The cave was unexplored, feared by many Ionians, yet she was willing to risk it all to satisfy her curiosity.
She had assembled a group of young adventures to help her explore it. In the cave, however, they found nothing but death. After 3 days of searching they were lost and had lost 4 party members to all kinds of monsters. Even though the rest of them went back, Gaia continued her search alone, and she went deep into the cave. There, she found a opening in the cave, yet it wasn't an exit. She had found something in that cave, yet she never told anyone what it is, and what happened in the deeps of that cave still remains a mystery. What is known is that when she came out all she saw was the suffering of her people under the Noxian occupation. Yet, before she even knew what to do in that situation, word came that Ionia had won the rematch. Thus her curiosity led her to learn about the League and as soon as she was ready she walked into the Institute of War and demanded to become a champion of the League. Even though she spent 12 years in that cave, she hasn't aged a bit.
I can never stop seeing her as helpless child - Soraka, the Starchild.

Got bored,so I decided to make a League Judgement.

OBSERVATION The great doors open as light pours in through them, revealing a thin silhouette of a woman. She walks elegant and slow, as she observes the walls around her. She seems intrigued, like a child, constantly holding a large smile on her face.
She seems to give away a faint blue shine from her skin. She looks away from people, trying to avoid interaction, like she is scared of them.
After a moment she loses the focus in her eyes, she starts daydreaming, looks straight forward and starts walking much slower. It looks like a trance, yet as soon as it began, the supposed trance was over.
She restores her focus and walks straight forward, unable to hide her excitement, she is eager to becoming a champion.

REFLECTION As soon as Gaia entered, senior Summoner Montrose tried to explore her mind, yet he could not. Something was blocking him.
-You are aware, child, that we have to explore your mind before letting you become a champion.
She quickly replied: - Feel free to. while smiling, giving off the feeling that she is deliberately trying to anger them.
-I can't, child. You have some warding magic protecting you. Lower your shield.
-I tough you summoners were powerful (laughs). *sigh* I can not, I have a promise to keep, a secret that I will not reveal.
Carin was quickly loosing patience. -We don't have time for silly games! Either lower the shield or leave!!!
-You are no fun. Very well, but I will have to censor most of it
And as a memory faded in, the summoners saw an old man, a teacher. He talked about the Starchild, how she should be Gaia's mentor, how she should stop her obsession and do what is right.
Quickly after that, the memory transits to a girl, trapped in a cave, all alone. She is scared, wounded and confused, yet she goes on. After that the memory stops and they return to the Institute.
-I can't let you see more.
-It was enough, Montrose replied -But you do know that you will be forbidden to use that warding magic on the Fields of Justice.
-Can I still protect my memories with it?'
-Yes, but nothing else.
That is fine, I don't need anything more to rip your poor champions apart. Take care.
As she leaves the summoners are left in confusion, they had never witnessed such arrogance.

Passive - Inner Sight For each point of Ability Power Gaia has, she gains 2 points of max. mana.
For every 40 points of bonus mana she has, she gains 1 point of Ability Power.
(Does not stack with itself, as in, she can get bonus Ability Power from the passive's mana bonus, but that Ability Power won't increase her mana all over again)
Also,all of the mana altering portions of her abilities will convert to a 20% reduced hp alteration, if the target is out of/doesnt use mana.
Possible icon: [2] Ability introduction:
It allows her to focus on increasing mana instead of AP and yet still increase the AP collateraly. It also makes a great combo with Mana Shield
And it allows her to target enemies with no mana, as she would be useless against manaless enemies otherwise.

Q - Mana Drain [Costs: 15% of max mana] [Base cooldown: 10/9/8/7/6]
:Drains 100/150/200/250/300 + (0.95 AP) mana instantly from the target. If the target has no
mana it will drain hp. She restores 80% of the mana/hp drained to herself over 3 seconds. When draining mana this ability will be affected by MR, and the MR will block it as if there were three times as much of it (for example, 30 MR would block the mana drain like 90 MR would do to the HP drain part). The mana drain will also not use Magic penetration, thus Magic penetration will not increase her mana drain.
Possible icon: [3] Notes:

-It is a single target ability that can only target enemy units.
-If the target has no mana (left) it will take damage equal to 80% of the supposed mana drain (80/120/160/200/240 (+0.76 AP)).
-If the target had mana but less than the mana drain amount the ability will first drain the mana and then convert the remaining amount into damage.
-If cast while with full mana this ability will regenerate the mana you have used and then convert the remaining amount into hp.
-The mana draining part of this spell does proc spell vamp, however it will give you only 25% of the actual spell vamp, while when draining hp it will give the full spell vamp.
-If the target has a shield, the ability will first damage the shield and then start draining mana/hp
-If targeting an enemy with a shield it will not return the damage blocked by the shield as mana/hp.
-It procs Rylai's Crystal Scepter's slow only upon the hp drain.
-The cast range is 750.
Ability introduction:
Gaia can easily use this ability to restore mana to herself, giving her great sustain in lane
and small damage. This ability allows her to dominate a lane against a mana
dependent opponent while being very weak against non-mana champions. The energy
draining part helps her stop energy dependent enemies from quickly casting spells and
forces them to walk back and wait for it to regenerate.

W - Soul Transfer [Costs: 25% of current mana] [Base cooldown: 25/22/18/15/12]
Gaia transfers 50% of the mana she used to cast this spell (+1% increased value per 20 AP)
to the target ally over 5 seconds
Her passive activates if the target has full mana or doesn't use it, thus healing
the target for 80% of the actual mana that was supposed to be restored.
Possible icon: [4] Notes:
-It is a single target ability that can be cast on allies or on yourself. It is a leash however and can be broken if the target walks out of range.
-This ability is a channel.
-It drains the mana required to cast it over the 5 second period, thus draining 5% of the
mana you had when u used it per second, and if you use an ability while the mana is being transferred and have less mana than the ability requires it will heal/restore for the remaining mana you have.
-The cast range is 450 but the leash range is 800 (if not targeted on yourself of course).
Ability introduction:
It isn't good to use it after Spell Chains because it reduces it's heal and vice versa.
And just for reference, if you cast this ability when having 5000 max. mana (full of course) and 800 AP, you will regenerate 1125 mana (1250 mana is 25% of 2000,90% of the used amount of mana regenerated = 50% mana used + 1% per 20 AP, which is equal to 90%, and that all adds up to 1250 mana and 90% of that amount) over 5 seconds to the target (or 900 hp), but if cast it on yourself however,
you will not regenerate all the mana you have used.

E - Spell Chains [Costs: 15% of current mana] [Base cooldown:14 seconds]
Gaia deals magic damage to the target enemy unit equal to 70% of the mana used (+ 0.4 AP) and roots it
for 1.1/1.2/1.3/1.4/1.5 seconds (+ 0.1 second per 70 mana used). Root can't last longer than 3 seconds. If it hits, you will have 5 seconds to
cast the ability again so you could dash to the target's position and increase your Armor and Magic Resistance by 20/30/40/50/60 for the next 3 seconds.
Possible icon: [5] Notes:
-It is a single target ability that can only target enemy units.
-It's cast range is 600.
-If it is targeted against a unit entering stealth and the unit enters stealth just before the
projectile(she) hits, the target will be rooted and revealed for 2/5 of the root duration.
Ability introduction:
It is an initiation ability because it has the highest damage and duration while cast at full
mana, and it's cooldown allows you to catch up to running enemies (or run away) as it's cooldown will be over, long after any team fight ends. Also she will gain more Armor and MR when cast with max. mana and they last for a very short duration so they help for the short burst damage she takes when initiating.
Upon casting she will quickly raise her hands (like in the picture bellow) and release 2 flying discs that follow a set path (also shown in the picture), quickly spreading to point A (speed of about 300) and then launching themselves with great speed (about 600) towards the target, and when they get close they turn into chains that wrap around the target. During the root the target will have a rune beneath itself (the one i used for the icon).
Visual representation: [6]

R - Mana Shield [Cost: 50 initial mana and then 12/16/20 mana per second +5 mana cost increase per second] [Base cooldown: 15/12.5/10]
Gaia creates a shield around her made out of pure mana, which reduces the effects of all CC on her by 50% as long as it holds. While the shield holds it will absorb 85% of damage taken and she will lose 4/3.5/3 points of mana for each point of damage absorbed. While on, she will gain a passive effect:
Whenever an unit uses an ability they will take magic damage/be healed by 3/4/5% of Gaia's missing mana (+1% for each 80 AP) and restore her mana by 80% of the damage dealt/healed..
Possible icon: [7] Notes:
-It is a instant spell that requires no target.
-Even though it can be turned on/off it doesn't count as a toggle (similar to Ramuss's
Powerball and Defensive Ball Curl), thus it procs Archangel's
passive, Maokai's passive etc. both when turning it on and off, but it wont proc her ult's passive.
-Has a 1 sec. cooldown before it can be deactivated.
-The CC effect reduction does not stack with tenacity and is not viewed as tenacity. It is a complete CC reduction and it will replace any tenacity she had.
-The CC effect reduction affects both their duration and effects (does not reduce the
duration of suppress).
-It doesn't have an casting delay and thus it won't disturb captures on Dominion.
-The passive's AoE is 1400.
Ability introduction:
Well it's a general utility spell giving Gaia a little bit of tankyness if she has the
mana.This makes Rod of Ages and Archangel's Staff perfect picks for her.
The mana cost however does make Chalice of Harmony a very important item for her.
And even though it has a very short cooldown it is very bad to randomly spam it cause it costs 50 mana each time, it's better to watch for the right moment.

Recommended items [Classic]:

Summoner's Rift

Additional Info:
Even though it isn't on the list of recommended items for normal mode, it is very important to acquire Frozen Heart early in-game as it gives her the crucial
cooldown reduction, a nice amount of mana and increased durability thanks to the armor bonus.

Recommended items [Dominion]:

Summoner's Rift

Original Link:

(I posted her there and got a lot of replies so i tough I'd post here here too :P )

There are lots of suggestions there besides mine, many of them are AWESOME.