Dota 2/Nyx Assassin

Nyx Assassin is a melee agility hero who is usually played as a ganker. He is very proficient at ganking, being a dangerous threat even during the later stages of the game. His Impale is a reliable stun that's similar to Lion's Earth Spike, helping him lock down heroes. His Mana Burn is especially effective against spellcasters, and scales with the target's intelligence, which makes him deadly at taking down intelligence heroes. His Spiked Carapace will counter all instances of damage when attacked by multiple sources, which is useful when he comes under fire from enemy heroes, as well as turning their aggression against them. His Vendetta is one of the strongest invisibility spells in the game, with a very long duration. Nyx can also attack out of it for massive damage, initiating a gank or finishing off an unlucky enemy. Nyx Assassin is a hero who is extremely powerful at picking off lone heroes, though he can also contribute to a teamfight with his potent stuns and by drawing attacks from enemies.

Impale
Impale makes spikes jut out of the ground in the direction of the target, stunning any enemy in its path. It is a good stun that does decent damage. It can easily stun multiple enemies with good positioning. It is a good way to initiate a gank, even better if you can catch another hero accompanying the target, as it lets you focus on your target without being disturbed from its partner.
 * Ability: Target Unit, Target Point
 * Affects: Enemy Heroes
 * Damage Type: Magical
 * Damage: 80 / 140 / 200 / 260
 * Stun Duration: 1.27 / 1.77 / 2.27 / 2.77
 * Mana Cost: 95 / 115 / 135 / 115
 * Cooldown: 11

Mana Burn
Mana Burn destroys the target's mana based on a multiplier of their intelligence, dealing the same amount of damage as the mana lost. It is a great damage nuke, especially against heroes with a high intelligence stat like Pugna. The mana drain can render them unable to use one of their stronger spells, which can make a caster helpless to fight back.
 * Ability: Target Unit
 * Affects: Enemy Heroes
 * Damage Type: Magical
 * Intelligence Multiplier: 3.5 / 4 / 4.5 / 5
 * Mana Cost: 100
 * Cooldown: 28 / 20 / 12 / 4

Spiked Carapace
Spiked Carapace temporarily reflects damage back to its source, negating the damage dealt to him and stunning the source of the damage. It can be very effective if enemies choose to concentrate their attacks on you, since you can brush off all of that damage while stunning groups of enemies. It can also make enemies scared to attack you as you pick them off one by one. Spiked Carapace can sometimes be the difference between surviving and dieing, as a well-timed activation will let you dodge a lethal attack and slow down your pursuers.
 * Ability: No Target
 * Damage Type: Pure
 * Reflect Duration: 2.25
 * Stun Duration: 0.6 / 1.2 / 1.8 / 2.4
 * Mana Cost: 40
 * Cooldown: 23 / 20 / 17 / 14

Vendetta
Vendetta turns you invisible, giving you bonus movement speed. Breaking the invisibility with an attack will let you do bonus damage. This spell is easily the strongest temporary invisibility spell in the whole game, lasting up to 50 seconds. You can use the high bonus damage to initiate a kill, or to finish a wounded enemy off by surprise. While it can be used as an escape mechanism, the high mana cost and cooldown might not be worthwhile if you can escape without it.
 * Ability: No Target
 * Damage Type: Physical
 * Duration: 20 / 35 / 50
 * Movement Speed: 16% / 18% / 20%
 * Bonus Damage: 250 / 400 / 550
 * Mana Cost: 160 / 210 / 260
 * Cooldown: 70 / 60 / 50