Iran, the great power Shiite supports the Iraqi government (Shia), but Bashar al-Assad, an Alawite (a branch of Shiism ) and the Houthi rebellion in Yemen. North Lebanon and the southern Syrian rampant Hezbollah militia Shiite who fights alongside the same Assad, against DAESH (Sunnism tends Wahhabi ) and alongside Iranian military advisers (Shia).
Saudi Arabia, the great sunni (Wahhabim) power, supports the sunni government of Yemen and funded the Hamas stationed in the Gaza Strip, which is an outgrowth Sunni Egyptian Muslim Brotherhood. It fights and it might seem surprising, DAECH. This is actually a question of survival for the Saudi ruling family, which risks losing its legitimacy in favor of jihadists.