Ally is a creature type introduced in the original Zendikar block, where Allies typically have abilities that trigger whenever they or another Ally enters the battlefield. Battle for Zendikar and Oath of the Gatewatch added a new mechanic in rally, which grants bonuses to your creatures when an Ally enters.
General Tazri tutors Allies and pumps the team based on the colors of Allies you control, while Harabaz Druid adds mana for each Ally on the battlefield. Hagra Diabolist and Kalastria Healer turn each new Ally into life loss for opponents, and Katara, the Fearless can double those enters triggers. Tuktuk Scrapper adds repeatable artifact removal that deals more damage as the Ally count grows.
