Damien is a fighter. Wields a grapling hook. His attacks are 300-ish. He disrupts enemies around the battlerfield while being durable and dealing great single target damage.

What doesn't kill ya... (Innate): Killing a unit increases Damiens base attack damage, armor, magic resist and attack speed by 15% for 3 seconds. Champion kills and assits cause this effect to stack two times and increase the duration of the buff to 5 seconds.

Not even one step further (Q): Damien extends his grapling hook damaging enemies in a line. The hook will immobilize a single enemy at the end of its range for 1.5 seconds.

Hooking up! (W): Damien starts swinging his hook. His next basic attack will gain additional range and will deal increased damage based on how long he was channeling. While channeling Damien gains movement speed and can not autoattack or cast spells.

Let me see ya now (E): Dissarms a target enemy champion making it unable to autoattack for 1.5 seconds and steals a percent of their attack damage for 3 seconds.

Gotcha, beasties!(R): Throws a massive net at a location for 3 seconds. Enemies caught in it are dealt magic damage and are slowed as long as they remain in the area. If Damien is above the net he can activate the spell again to throw himself a fixed distance in the direction he is facing.

His story:

Damien was a bounty hunter, hunting or exterminating evil creatures on demand of villages across Valoran. Once his travels lead him to the Shadow Isles where he ventured to the Skull Mountain. He hunted a beast that once slaughtered his family. He carried all that he needed, a grapling hook to help him climb the mountain. Once he reached the mountain top an epic battle begun. Damien used the grapling hook as a weapon and after a hard fight he defeated the beast. But the curse of the beast bound him to Shadow Isles. He could not leave and was traped on a island of death and pain. He did there what he he knew best, with grapling hook as his main weapon he survived for a long time on the Shadow Isles, becoming the evils worst nightmare. Summoners heard of such an incredible will to survive, they managed to break the curse and free Damien who in favor wanted to fight in the League of Legends.