Dota 2/Leviathan the Tidehunter

Tidehunter is a melee strength hero known for being one of the best initiators in the game, as well as being a good support. His Gush will slow down enemies as well as knock their armor off. His Kraken Shell lets him survive and escape even when all enemies are focusing on him. His Anchor Smash will weaken foes and do area damage. Finally, his signature ability Ravage will quite literally ravage the enemy team, having a massive area.

Gush
Gush launches an orb of water at the target, damaging it, slowing and reducing its armor. It is a very decent slow, and the armor reduction synergises with your Anchor Smash since it does physical damage. It also helps your carries take down key targets faster.
 * Ability: Target Unit
 * Affects: Enemy Heroes
 * Damage Type: Magical
 * Damage: 110 / 160 / 210 / 260
 * Slow: 40%
 * Armor Reduction: 2 / 3 / 4 / 5
 * Mana Cost: 120
 * Cooldown: 12

Kraken Shell
Kraken Shell will passively reduce the physical damage you take, but more importantly it will remove all status effects whether it'd be a stun or slow when you take more than 600 damage. This makes you very durable, since if the enemy team tries to focus on you with disables, they are only making it easier for you to escape. A side note, is that Kraken Shell will not stack with damage block items like the Stout Shield.
 * Abiltity: Passive
 * Damage Reduction: 7 / 14 / 21 / 28
 * Damage Threshold: 600

Anchor Smash
Anchor Smash makes you swing your anchor, damaging enemies in a deceivingly large radius around you as well as reducing their physical damage. It is decent for an area of effect ability, and the damage reduction is useful for harassment and weakening carries. Once you have a large enough mana pool, feel free to spam this, since with a cooldown of only 4 seconds at level 4, you can use it very often.
 * Ability: No Target
 * Damage Type: Physical
 * Damage: 75 / 125 / 175 / 225
 * Damage Reduction: 40%
 * Duration: 6
 * Radius: 400
 * Mana Cost: 30 / 40 / 50 / 60
 * Cooldown: 7 / 6 / 5 / 4

Ravage
Ravage causes tentacles to spring out in a massive area around you, stunning and dealing damage to all enemies caught by it. When you think of Tidehunter, you think of Ravage. There are really few initiation abilities that can rival this. Use it as a very effective way to start a teamfight, leaving your enemies at a health, and maybe even hero, disadvantage.
 * Ability: No Target
 * Damage Type: Magical
 * Damage: 200 / 325 / 450
 * Radius: 825 / 925 / 1025
 * Duration: 2.02 / 2.32 / 2.77
 * Mana Cost: 150 / 225 / 325
 * Cooldown: 150