Aghanim's Scepter

Aghanim's Scepter is an Item purchasable at the Main Shop, under Caster. However, it can only be completed with items from the Secret Shop. This item is used to increase the power of a hero's Ultimate ability (with the exception of Tinker and Ogre Magi, whose abilities are augmented instead), which makes it an excellent weapon for a Nuker or a Support type hero.

Trivia

 * Aghanim's Scepter is named after Agahnim, one of the main villains in The Legend of Zelda: A Link to the Past.
 * In both DotA and Dota 2, Rubick is the son of Aghanim. He also possesses an imitation of.
 * No hero responses (except Razor) include Aghanim's name when purchasing Aghanim's Scepter; they simply refer to it as the 'Scepter'. Eul's name also shares the same treatment when heroes purchase Eul's Scepter of Divinity.

List of Upgraded Ultimates
There are currently 59 of the 107 heroes whose ultimates are upgradable by Aghanim's Scepter, meaning just over half of the current hero pool benefits from this item. The remaining 48 heroes will only gain the stat bonuses if Aghanim's Scepter is purchased.