Champion idea: Hepharius

Hepharius the thumping Vengence

Demacian with a two-handed greathammer

Stats: Health-564.38 (+96 per level)

Mana- 274 (+34.5 per level)

Health Regen- 8.935 (+0.8 per level)

Mana Regen- 6.095 (+0.33 per level)

AD-54.67 (+3.1 per Level)

Attack Speed- 0.629 (+1.89% per level)

Movement speed- 330

Armor- 28.79 (+2.9 per level)

Magic Resist- 29.02 (+2.1 per level)

Ablities:

Passive-Armorer's Heat: Basic Attacks lower enenmies armor. Lvl1: 5(+25%ad), lvl11: 10(+25%ad), lvl16: 20(+25%ad)

Q- Thwack- With in a frontal cone knocks back all enemies, any enemy hit by a knocked back enemy will be stunned for 1.5 seconds. 80/110/130/150/170(+0.75 ad ratio). Mana cost: 50 all ranks, Cooldown: 14/13/12/10/9 seconds

W-Hardened Velocity Passive: Adds 8/10/12/14/16 attack damage and 10/14/18/22/26 armor.

Active: loses passive bonus to gain 70% movement speed(Decaying) that knocks all enemies back while running forward for 4 seconds, enemies hit like this take 25/30/35/40/45 (+ 2.5% current target health) as damage. (Can still be disabled when active)
Mana cost:65/70/75/80/85 Cooldown: 25/23/21/19/17 seconds

E-Whirling Slam Slams the hammers pick into the ground, using his body to spin one rotation in a circle dealing 110/130/160/190/210(+0.6 attack damage) to all enemies hit. Mana cost:45/50/55/60/65 Cooldown:15/12/10/9/8 seconds

R-You Get a Thumping Slams hammer into the ground stunning enemies hit while in the center of it by 2 seconds and dealing 150 (+.125 Attack damage). Enemies hit on the outer edge are slowed for 30% for 2 seconds and take 75(+.125 Attack damage) of damage.
Alternately a shock wave emanates from the slam revealing all unseen enemies for 1.5 seconds. Mana Cost: 130 all ranks Cooldown: 160/120/100 seconds Slam radius: 450 units

Lore: "Demacia has always been known for it's strength and fortitude. Hepharius is no exception. Once a mighty Demacian Knight, he had many battle experiences alongside a close friend of the family: Jarvan IV. After a close encounter with an unknown creature, Hepharius barely escaped, coming back to the kingdom bloody and bruised. He looked on with sorrow at Jarvan asking for forgiveness. But the Prince had to upheld his code. No warrior runs from a battle. He was exiled.

After several years alone in the wilderness, he trained and trained until his strength became immense. He joined Noxus in hope to earn some cash for his achievement of strength. However, this proved to be almost deadly, again. A dragon, bigger than any ever known to man, appeared before Hepharius. This was the same dragon Jarvan once had hoped to kill.. he could tell by the gravely wounded posture it was in. However, the dragon rushed at him to attack. He felt it again.. the same creature who came back to claim his life. Hepharius picked up his armor and began to run when he tripped. A large thump toppled the dragon. He looked up to find a hammer big enough for him to wield forcefully, and picked it up. He was about to swing, when the dragon knocked him away with his wings. He went flying off and almost fell off the cliff at the top of the mountain he was fighting. He then slid down, and the dragon began to rest. He stayed there, waiting for a place to strike, when all of a sudden, familiar faces showed themselves. Jarvan IV, his long lost friend, was leading a brigade to end that dragon's life. But this strange girl was with them, she looked very vicious and very deadly. But, Hepharius wasn't fearful of her like the rest of the other warriors looked. He looked on, studying the girl with careful precision. At the end of their battle with the dragon, he saw that Jarvan offered her a spot with the Elite Guard, his old position. He became furious with rage and roamed off until the world could no longer find him. He began training more, thumping louder and louder in the forest, until one day, he could challenge the girl and reclaim his spot among the Demacians. Hopefully. Until that day, he will continue to thump with amazing power, and be known as the Thumping Vengeance.

That dream was put on hold when the League asked for his help. He knew that the girl also served for the League and graciously accepted. One day, he will have that battle. Just you wait.