Dota 2/Demnik Lannok the Warlock

Warlock is a ranged intelligence hero who can be played as a support and sometimes as an initiator. Along with powerful disables and damage spells, he also gives his team a useful heal. His Fatal Bonds becomes more deadly the more heroes he catches with it, and can indirectly amplify his team's damage output, spreading it out to other heroes. He can use Shadow Word to heal or to damage, being effective at both. His Upheaval will cripple enemies, setting up other initiation abilities for his team. His ultimate, Chaotic Offering, actually lets him summon and control an hellish Golem, dealing huge amounts of damage in large teamfights.

Fatal Bonds
Fatal Bonds binds enemy units near the target. 20% of the damage taken by any one of the bound units will be dealt as hp removal damage for all other bound units. This spell can becomes very effective if you catch several heroes with it. It lets your allies focus on an heroes while dealing heavy damage to other heroes. AoE damage also becomes more powerful, as hitting multiple bound enemies will make them take the spell's damage in addition to the bonus damage from Fatal Bonds.
 * Ability: Target Unit
 * Affects: Enemy Heroes
 * Damage Type: HP Removal
 * Enemies Bound: 3 / 4 / 5 / 6
 * Duration: 25
 * Mana Cost: 120
 * Cooldown: 25

Shadow Word
Shadow Word places a buff that heals an allied unit or a debuff that damages an enemy unit every second. It;s appplication should be obvious. You either place it on wounded allies to keep them alive or you place it on enemy heroes to wear them down. The heal/damage is actually quite high compared to other abilities that damage or heal, at 405 for level 4.
 * Ability: Target Unit
 * Affects: Heroes
 * Damage Type: Magical
 * Damage: 15 / 25 / 35 / 45
 * Duration: 9
 * Mana Cost: 90 / 110 / 130 / 150
 * Cooldown: 20

Upheaval
Upheaval slows all enemies caught in it, with the slow getting more intense the longer the spell lasts, up to an 84% slow. The spell lasts 10 seconds and enemies will still be slowed for 3 seconds after they leave the area or after the spell ends. The ability is channeled, which means that you can't do anything while the spell is being used, and a simple mini-stun will interupt the spell. The slow is very strong, and enemies will usually be slowed to the minimum move speed cap by the end of the spell. Since enemies caught in it will have a hard time escaping, you can use it to help set up other initiation spells for your team.
 * Ability: Channeled, Target Point
 * Radius: 650
 * Slow Rate: 7% / 14% / 21% / 28%
 * Mana Cost: 100 / 110 / 120 / 130
 * Cooldown: 50

Chaotic Offering
Chaotic Offering summons a Golem, dealing damage and stunning for 1 second to all nearby enemies upon its arrival. The Golem lives for 60 seconds, or until it is defeated. It is a great teamfight ability and can be used to initiate fights. The Golem itself is quite capable of doing high damage especially with Permanent Immolation. With a bit of micromanagement, you can do a lot of damage by using your spells and the Golem's attacks.
 * Ability: Target Point
 * Damage Type: Magical
 * Radius: 600
 * Damage: 100
 * Mana Cost: 200 / 250 / 300
 * Cooldown: 165
 * Scepter Number of Golems: 2
 * Scepter HP/Damage Reduction: 25%
 * Scepter Bounty Reduction: 50%

Aghanim's Scepter can be bought by Warlock and will make Chaotic Offering summon two Golems that only have 75% damage and hp, but give 50% less gold when killed.