The Islamist rebel factions that still hold key districts on the outskirts of Damascus are facing a new enemy from an unlikely source: former rebels who have formed a pro-Assad militia.

Dubbed the Jaish al-Wafaa, or “Loyalists’ Army,” the group has been around for a few months, according to officials familiar with them, but has only gotten active very recently, with a weekend attack on the suburb of Douma amounting to some of their heaviest fighting yet.

The Islamist rebels in Douma have fought the military to a stalemate for over a year, but this new Loyalists’ Army includes a lot of their former allies, who have decided to change sides, and have considerable insight in these groups that the military lacks.

Many of the fighters are even from Douma originally, and switched sides with an eye on helping their families evacuate into safer, government-held portions of the capital.

It’s not entirely a cynical change, however, as many say that the Islamist leader of Jaish al-Islam, the Islamic Front wing in charge of Douma, has been extremely abusive to locals.

Ironically, the Islamic Front is seen as one of the more moderate Islamist factions, compared to the likes of ISIS and al-Qaeda’s Jabhat al-Nusra. Here in the capital, it seems, they’ve had their fill even of so-called moderates, and are deciding the rebellion, which is now almost exclusively led by Islamist factions, has gotten terrifyingly off-track.