My concept for a gravity controlling mage that counters mobility.
I'm not the best at creating lore and art, so I'll leave the name and art to Riot/you guys.
Passive : Gravity Manipulation (This is the complex part)
(The champion will be referred to as X) Hiting enemy champions with X's Q or E applies an effect called "Affected by gravity". Hiting an enemy champion that is "Affected by gravity" does a lot of bonus damage and removes the effect. Enemies need to be "Affected by gravity" to be hit with X's W, which also removes the effect. Also, X's auto attacks do bonus magic damage but have a cast time (X pulls a rock from the ground and then throws it).
Q: Gravity Push (Cooldown should be from 7 to 5 seconds) Applies "Affected by gravity" Shoves a targetable object (minions, monsters, player summoned minions) or the meteor called by her E, doing magic damage to the first target hit. If the meteor is thrown, it does AOE damage as it explodes (which means you can't reuse the meteor). This has a short cooldown. (Can be used with nothing to throw, but has double the cooldown if you do. This is for the moments you need to shove someone away with your W). Does medium magic damage.
W: Gravity Pulse/Gravity Pull (Cooldown around 20 seconds) If Q was the last ability used, it pushes enemies in an area around you away. If E was the last ability used, it pulls enemies in an around you towards you. Needs "Affected by gravity" to be applied on the enemies and consumes it. Does a small amount of magic damage.
E: Meteor (Cooldown: 17/16/15/14/13) Applies "Affected by gravity" Uses gravity to pull a meteor from the skies, which stays on the ground for (subject to change) 6 seconds. Stuns in the center and slows at the edges. Does high magic damage.
R: Intense Gravity (Cooldown: 140/110/90) Creates a relatively big zone that grounds everyone inside (allies included) and "suppresses" movement speed buffs (meaning that they are still active, just not effective inside the zone). May or may not apply "Affected by gravity" to enemies inside, depending on balance.
The kit works because it has a lot of defining strengths and weaknesses, and because it has counterplay. The Q cannot reach its full potential if there's nothing around to throw. And even if you have Meteor up, you might end up not wanting to use it to keep the stun and AOE for fights.
An other aspect that gives counterplay to the kit, is that "Affected by gravity" makes you chose between CC (W) or the damage proc. W also makes you chose between a defensive and an offensive use. This means you have damage and CC, but it gives the player meaningful gameplay decisions on which to use.
Finally, the weakness of the ultimate is easy to see, a bad use can screw over your team.
If you have something to add or change, positive or negative criticism to make, or if you have an idea for the lore and character, feel free to comment. I will actively reply and edit the concept and mention you.