According to the New York Times, details on Duhine's background before joining remain unclear, though he previously served as Abu Shabab's deputy.
The Popular Forces, operating in an Israeli-controlled zone near Rafah, is seen as the most structured among several small militias Israel has supported to undermine Hamas since the war's early stages.
Israeli officials have acknowledged arming the group, despite Abu Shabab's denials, with the militia securing areas to allow Israeli troops to redeploy elsewhere.
A retired Shin Bet official described them as functioning like a military unit on missions.
Abu Shabab, a Bedouin from southeastern Rafah, gained notoriety in late 2024 for alleged aid convoy raids amid Gaza's hunger crisis.
His death, amid a dispute with a Palestinian clan, prompted Hamas's interior ministry to hail it as the "inevitable fate of every traitor" and issue a 10-day ultimatum for similar militias to surrender.
This leadership shift highlights risks in Israel's strategy of backing local forces to stabilize post-ceasefire Gaza, as Hamas seeks to reassert control.