The Intercept has the inside scoop, a leaked document from Iran’s intelligence service, MOIS.
The Quds Force represents the world’s most powerful Shia-dominated nation, while the Muslim Brotherhood is a stateless but influential political and religious force in the Sunni Muslim world.
Source: Iran’s Quds Force and Muslim Brotherhood Considered Anti-Saudi Alliance
Both organizations are demonized in the Washington, not the least because they share a common enemy: Saudi Arabia.