Lauren, The Disrupted
Thought I'd give a shot at designing a champion that will most likely be broken or beyond useless but here we go.
Lauren, The Disrupted
Primary role: Fighter/Mage
Lauren was an apprentice in a highly adept school in Ionia, learning how to harness her natural gift for conjuring flame and manipulating its shapes through different weapons. Feeling that she had moved beyond her studies, she left and became a wanderer and traveled throughout Runeterra to get some real world experience with her craft. Sword in hand, she defeated many creatures and slayed many enemies, from the deserts of Shurima to the lowest slums of Zaun. During a visit to Bilgewater, she came across Illaoi, The Kraken Priestess. Lauren took her test and was ultimately defeated, but as Illaoi attempted to steal her soul the magic inside Lauren rose up and attempted to interrupt the ritual. Illaoi's powers were interrupted, but Laurens soul was partially ripped out but still attached to her being, while the rest of it was slipping away, causing her abilities to drastically change. Feeling cold and empty, Laurens new goal is to find Illaoi and force her to undo the damage she had done to her so she could feel complete again.
Friends:
Enemies: 
Abilities:
Passive: When Lauren uses an ability, she fills up one tick on her resource bar. After hitting champions with 10/9/8 abilities, she gains access to her ultimate, Soul Seeker.
Additionally, whenever Lauren uses an ability, a copy of the ability activates .75 seconds after, having additional effects depending on the ability used.
Damaged respite (Q): Lauren lunges forward to slice all enemies in a cone, damaging all enemies hit. After .75 seconds, Laurens soul does the same maneuver, but instead of a slash, she unleashes a longer and wider range flame cone attack, slowing all enemies by 50/55/60/65/70% for 2 seconds. The first strike scales with AD, the 2nd strike scales with AP. This skill has a very short cool down.
Injured essence (W) : Lauren dashes (about the range of Rek'Sai's E)forward in a line slicing all enemies hit along the way with her sword. After .75 seconds, Laurens soul follows, leaving behind a wall of blue flame from the starting position to the end lasting for Enemies that pass through or stand in the fire take damage and are afflicted with grievous wounds for 3/3.5/4/4.5/5 seconds. Allies that pass through the flame reduces the recharge of this skill by 1 second once per ally. The first strike scales with AD, the 2nd strike scales with AP. This skill has a fairly long cool down.
Desolate feelings (E): Lauren jumps in the air towards the mouse curser and slams down, damaging all enemies in an area (think the size and range of Mega-Gnar's E) and stunning them for 0.5s if the skill shot hits both the enemy and the flame caused by her W. After 0.75 seconds Laurens soul flares up the edges of the landing site, damaging again and knocking up all enemies for 1 second if they remain near the outside of the original landing zone. The first strike scales with AD, the second, with AP. This skill cannot cause Lauren to go over any walls or terrain. This skill has a somewhat short cool down
Heart and Soul (R): Lauren and her soul attempt to rejoin each other, conjuring a column of extremely unstable spirit energy. After channeling for 2 seconds the pillar of energy splits into 5 (or however many champions are on the enemy team) vertical beams that globally go out in the direction of all enemy champions. The beams move faster the longer they are on the battlefield. The beams very slightly home in on enemy champions but are still able to be dodged. Enemies hit with multiple beams take reduced damage but are inflicted with grievous wounds. This skill scales with both AD and AP. This skill has no cool down. Any hard CC such as stuns, taunts, or knockups will interrupt the channel. If the channel is interrupted her resource bar ticks reset to 0.
That's about it really. I'm by no means a good champion designer and I left out some numbers (such as the AD/AP scalings) because I have a horrible sense of balance. The kit probably makes 0 sense or probably wouldn't even function but I tried to be original as I could in regards to the other champions and their kits.
What are your thoughts? What would you change? Discuss below :)