Hero Attributes are the three main aspects found in all heroes that determine the five scaling values of Hit Points, Mana Points, Armor, Attack Speed, and Damage.
These attributes are Strength, Agility, and Intelligence. Attributes can increase by leveling up, taking points in Attribute Bonus, buying certain items, and using certain abilities.
 Primary Attribute
Of the three attributes, each hero specializes in one. This is called the Primary Attribute and it determines their attack damage. Each point in the primary attribute increases attack damage by one. Usually a hero's primary attribute will grow faster than the other two attributes. Every hero gains a constant amount of Strength, Agility, and Intelligence per level unique to their hero.
Strength is one of the three attributes possessed by all heroes. It increases maximum health and health regeneration.
Strength heroes usually fit the Initiator and Durable roles. There are 37 Strength heroes in total.
Each point of Strength:
- Increases Hit Points by 19
- Increases Hit Point Regeneration by 0.03 (every 33 points = 1 hp regen)
- Increases the damage of Strength heroes by 1
Each point of Agility:
- Increases Armor by 0.14 (every 7 points = 1 armor)
- Increases Attack Speed by 1
- Increases the damage of Agility heroes by 1
Intelligence is one of the three attributes possessed by all heroes. It increases maximum mana and mana regeneration.
Intelligence heroes usually fit the Nuker and Support roles. There are 40 Intelligence heroes in total.
Each point of Intelligence:
- Increases Mana Points by 13
- Increases Mana Point Regeneration by 0.04 (every 25 points = 1 mana regen)
- Increases the damage of Intelligence heroes by 1
 Attribute Bonus
Attribute Bonus is a passive ability possessed by all heroes except Invoker. Each level of Attribute Bonus increases all attributes by 2. Attribute Bonus is distinct from the automatic attribute increases gained by every hero at every level. Just like regular abilities, Heroes can place a new skill point in Attribute Bonus by clicking on the stats panel. It becomes available at every odd numbered level. Though it is typically leveled last in favor of leveling abilities first, Attribute Bonus can be leveled a maximum of 10 times at levels 1 / 3 / 5 / 7 / 9 / 11 / 13 / 15 / 17 / 19 at the earliest. Attribute Bonus is a convenient way to compensate for a Hero's early game weakness without filling inventory space. For example, Skeleton King and Sven have very low Intelligence, so they often take a few early levels of Attribute Bonus to improve their mana pool. Adding one level to Attribute Bonus is functionally equivalent to having a Circlet or two Iron Branches. Especially when behind or losing, it is statistically beneficial as an extra level up. For example, a level 3 hero with 1 point in Attribute Bonus is nearly as durable as a level 4 hero.