Attributes

Attributes are the main statistics of all heroes that independently determine most scaling statistics. These attributes are strength, agility, and intelligence. Attributes are gained when a hero levels up, obtains a talent, buys certain items, or uses certain abilities. Illusions benefit from attributes.

Primary attribute
Every hero has a primary attribute, which controls their attack damage. Every point in their primary attribute adds point of damage to their attacks. Heroes also gain 25% more stats from each primary attribute point than other heroes do. A hero's primary attribute heavily impacts and commonly even defines the hero's role and how they are played. For example, intelligence heroes are typically more dependent on abilities. A hero's primary attribute typically grows faster than the other two attributes.

Strength
Strength is a measure of a hero's toughness and endurance. Strength determines a hero's maximum health, health regeneration, and additionally magic resistance. Heroes with strength as their primary attribute can be hard to kill, so they often take initiator and tank roles, initiating fights and taking most of the damage from enemy attacks.

For agility and intelligence heroes, every point in strength
 * Increases maximum health by.
 * Increases health regeneration by.
 * Increases magic resistance by %.

For strength heroes, every point in strength
 * Increases attack damage by.
 * Increases maximum health by.
 * Increases health regeneration by.
 * Increases magic resistance by %.

Agility
Agility is a measure of a hero's swiftness and dexterity. Agility determines a hero's armor, attack speed, and additionally movement speed. Heroes with agility as their primary attribute tend to be more dependent on their physical attacks and items, and are usually capable of falling back on their abilities in a pinch. Agility heroes often take carry and Gank roles.

For strength and intelligence heroes, every point in agility
 * Increases armor by.
 * Increases attack speed by.
 * Increases movement speed by %.

For agility heroes, every point in agility
 * Increases attack damage by.
 * Increases armor by.
 * Increases attack speed by.
 * Increases movement speed by %.

Intelligence
Intelligence is a measure of a hero's wit and wisdom. Intelligence determines a hero's maximum mana, mana regeneration, and additionally spell damage amplification. Heroes with intelligence as their primary attribute tend to rely on their abilities to deal damage or help others. Intelligence heroes often take support, gank, and pusher roles.

For strength and agility heroes, every point in intelligence
 * Increases maximum mana by.
 * Increases mana regeneration by.
 * Amplifies spell damage by %.

For intelligence heroes, every point in intelligence
 * Increases attack damage by.
 * Increases maximum mana by.
 * Increases mana regeneration by.
 * Amplifies spell damage by %.

Items improving attributes
Each attribute has its own set of items that focus on boosting it. These items are different for each attribute. In order to categorize them, they're split into 5 different sections:
 * Simple Items boost their associated attribute by 3. These items can be built into their Upgrade Item, and are usually taken as starting items to make up for gaps in a hero's statistics. The Iron Branch costs gold while the other 3 cost 135 gold each.
 * Upgrade Items boost their associated attribute by 7 and the other two attributes by 3. They are made by combining an attribute's Simple Item, a Circlet, and a recipe. They're generally taken if a hero is having difficulty reaching their core items. The Magic Wand costs gold while the other 3 cost 465 gold each.
 * Medium Items boost their associated attribute by 6. Though generally not taken to increase attributes, these items are usually components of many midrange items, and can all be combined with Boots of Speed and Gloves of Haste in order to build Power Treads. They cost 450 gold each.
 * Large Items boost their associated attribute by 10. These items are usually components in more powerful items, and all combined with Point Booster are used to make Aghanim's Scepter. They cost 1000 gold each.
 * Ultimate Items boost their associated attribute by 25. These are mostly used to make late game items because of how expensive they are. Their costs differ between attributes.