Dota 2/Dragonus the Skywrath Mage

""Nevermore to see my Skywrath home, that would be worse than any death.""

Skywrath Mage is a ranged intelligence hero who is usually played as a semi-carry or support who can do tons of magical damage, even as the game drags on. His Arcane Bolt scales with his intelligence stat, letting him maintain a high damage output throughout the game with the right items. His Concussive Shot is a useful slow and deals damage in an area of effect. Ancient Seal is a useful disable, while rendering Dragonus' target more vulnerable to his other spells. His ultimate, Mystic Flare, does huge damage in an area for a short moment, capable of killing most similarly-leveled heroes that stays in it for the whole period. While he has below average physical damage and agility, Skywrath mage more than makes up for it with his sheer magic damage.

Arcane Bolt
Arcane Bolt launches a slow-moving projectile at the target, doing damage depending on your intelligence. It is a spammable nuke that scales quite well into the late-game, when other spells generally become much weaker. The low cooldown and cheap mana cost lets you use it repeatedly.
 * Ability: Target Unit
 * Affects: Enemy Units
 * Damage Type: Magical
 * Base Damage: 60 / 80 / 100 / 120
 * Intelligence Damage Multiplier: 1.6
 * Mana Cost: 70
 * Cooldown: 5 / 4 / 3 / 2

Concussive Shot
Concussive Shot launches a projectile that flies to the closest enemy hero, dealing damage and slowing all nearby units on contact. It is a decent disable that also deals damage, though Arcane Bolt does much more later in the game.
 * Ability: No Target
 * Damage Type: Magical
 * Shot Range: 1600
 * Damage Radius: 200
 * Damage: 50 / 100 / 150 / 200
 * Slow Duration: 4
 * Slow: 40%
 * Mana Cost: 110
 * Cooldown: 20 / 18 / 16 / 14

Magic Seal
Magic Seal silences the targeted unit and amplifies the magical damage dealt to it. The increase in magical damage makes your spells deadlier against that specific target. The silences is also helpful against spellcasters, so casting it on a squishy support can quickly render them useless while you finish them off with Arcane Bolts.
 * Ability: Target Unit
 * Affects: Enemy Units
 * Magic Resistance Reduction: 18% / 24% / 30% / 36%
 * Duration: 3 / 4 / 5 / 6
 * Mana Cost: 80 / 90 / 100 / 110
 * Cooldown: 11

Mystic Flare
Mystic Flare creates a field of powerful magic that does humongous damage to enemy heroes inside for a short duration. The damage will be divided evenly if multiple enemy heroes are caught inside. It is best used for ganking and finishing off heroes due to its great range and high damage against single heroes.
 * Ability: Target Point
 * Damage Type: Magical
 * Radius: 270
 * Duration: 2
 * Damage: 600 / 900 / 1200
 * Mana Cost: 350 / 575 / 800
 * Cooldown: 60 / 40 / 20