Kaidan, the Tormented Warlock
Hi, welcome to the champion concept for Kaidan, the Tormented Warlock. (his backstory, special interactions, and more will be added later).
Basics:
Home: No known home. Nomadic.
Stance: Corrupt / Evil
Class: Mage
Secondary: N/A
Lane: MID Lane (or support), high control
Friends: 
Rivals: N/A
Powers:
Passive: Glyph of Fear
As Kaidan attacks a target, they begin to grow a glyph beneath them. Once the glyph reaches 20 power, it explodes dealing magic damage and applying the debuff of fear. The glyph glows a light blue, then blue, then purple, then a bruise-like purple before it pops.
Basic attacks - 2 basic attacks for 1 stack
Q - 2 stacks, 3 once fully leveled
W - 3 stacks, 4 once fully leveled
E - 4 stacks, 5 once fully leveled
R - to be determined
Amount of damage: 85 extra magic damage.
If Kaidan switches targets, the glyph remains for 5 seconds before it fades. If it is at stage 4, it begins loosing stacks instead of fading away completely. 1 stack every second.
Q: Blast of Darkness
Range: 1000
Cost: 55/60/65/70/75
Kaidan calls upon his internal darkness to blast an area for x magic damage. His Q is an AoE or circle form that hits multiple targets in an area.
60/100/140/180/220 (+0 AD and 65% of AP) magic damage.
Cool down: 6 seconds
W: Stop... Still... Silence or Black Hole
Range: 975 or 750 (975 option 1, 750 option 2)
Cost: 50/65/80/95/110
(Option 1): Kaidan damages an enemy from afar and curses with the inability to speak or cast spells (silence). This a targeted ability that only hits one unit.
(Option 2): Kaidan creates a large, circular hole that sucks enemies into its center, holding them there for 1/1.5/2/2.5/3 seconds (its a large root, kind of like Nami's bubble). This is an AoE that can hit multiple units.
70/110/150/190/230 (+ 0 AD and 35% of AP)
Cool down: 9 seconds
E: Shadow's Hand
Range: 1150
Cost: 60/70/80/90/100
Kaidan creates a shadow hand behind an enemy unit that begins to drag down back towards his location, pulling anything and everything in its way back with it. Kaidan may disarm the hand early if too many people are captured. The hand will also pull back allied units. Enemies hit by the hand are dealt 50/90/130/170/210 (+0 AD and 75% of AP) magic damage. Enemies may dodge the hand, but they may not leave the hand. (For quick reference, see Lissandra's E)
Cool down: 11 seconds
R: Dimension Walker
Range: 99999999999999999+
Mana: 130/120/110
Kaidan crafts a portal to walk the face of Runeterra. Allies and enemies alike may walk through the portal. Yet, enemies are dealt damage if they decide to walk through the portal. Kaidan must decide the start of the portal and the exit of the portal. The entrances and the exits will be visible to both ally and enemy alike. Kaidan may not choose fountains. Also, Kaidan's portal lasts 3.5 seconds and takes 2.5 seconds to create. This portal may also be sought by enemy units and destroyed. The portal has 1000 health.
Damage: 300/400/500 (+ 0 AD and 110% of AP)
Cool down: 100 seconds
(This art is not mine. It is to be used solely as an example.)
Only, Kaidan looks younger.
Lore:
Kaidan De LeMoy was a proud and meritable man with a deep, unnatural connection to the spirit world. He wrote several hundreds books and stories about the research he'd gathered from the spirits of various realms. How to cure possessions, ward off weakening walls between the mortal world and the land of demons and spirits.
Kaidan was going a good direction and fast with his life. Well, that was until he encountered a certain spirit of the night that changed his life forever.
Kaidan's connection to the land of spirits was so great and powerful that he entered that realm whenever he slept, sometimes he fall into other more... infernal... worlds.
On that one fateful night, he'd entered a new world. A place devoid of color, life, and sound. He ventured forth, excepting to be welcomed by several kindred souls of the dead and spirits of compassion, love, and grace... but he found none of that. Instead, he found a vast, swirling chamber of darkness plagued with ghoulish spirits flying up to its hellish center.
Kaidan had never seen something so dark, twisted, and overall, evil in all of his life. He tried to thrust himself wake but to no success. Panicked, Kaidan tried again, and again, again... each time failing. In fact, he felt as he was tethering himself more to the world the more that he tried to escape it.
His panic slowly slipped into fear, but then, a loud, mind shattering crackle sounded through his head, shattering it in two. His vision blurred as a dark, floating cloud appear before him. It held no shape, and most of all, no face. Kaidan looked curious and afraid, and instead of running off in fear, he reached out to touch it.
As he did, the creature sprung on him. Swirling around his mind like a flock of murderous crows. It's darkness swirling in his head, filling it with horrific visions. Visions of destruction, death... his death. A bloody manslaughter that left him in pieces. Kaidan yelled out in pain, reaching through his bond to the mortal and spirit world and brought his magicks through the bond.
He buried himself blue flame that loosened the creature tie to him... but still it grasp him, down to his very soul. Kaidan pulled more and more of his magic from the bond and into the hellish realm, until he and creature were engulfed in flame.
The creature, knowing it would loose, allow the flame to consume it, but it didn't free Kaidan. No, instead it infected his bond with it's dark curse. His flames grew from their bluish tint to a dark, sinister purple. The feeling of the creature morphing Kaidan's gave him the power and strength he needed to break free of the creature's grasp and re-enter the world of man. Kaidan ran, summoning a portal with a simple wave of his hand and dashing through it without a second thought.
Once Kaidan awoke the next morning, he felt different. His eyes saw the world in a new light, and his heart gave him feelings of those he loved a completely different twist. When he looked himself in the mirror, he could only the darkness of the realm he'd entered the previous night, and the creature that attacked. And for some reason, he could hear the creature's name whispering in his ear.
"Nocturne."
That name brought a smile to his lips, despite himself. Kaidan engulfed his hand in dark flame and fired it at his mirror, which melted into ash in a second. Kaidan had found new magicks, had become a new person, and was ready to show the world who he was whether they were ready for him or not, and his new found friend.
). The total time would vary of course. I think max time would be 5 seconds? The portal could also take more time to create the further out it is? Lots of ideas here. I'll keep yours in mind though.