On his return from Egypt, he was ordered to proceed to the Jaziran border zone ("thughur"), where the Byzantines, taking advantage of the rebellion of Husayn ibn Hamdan, had captured the fortress of Hisn Mansur and deported its population. In retaliation, he led a major raid in late summer 916, capturing several fortresses in the vicinity of Malatya, while ordering Abu'l-Qasim Ali to lead another raid from Tarsus. In September/October 917, in response to a Byzantine embassy led by John Rhadenos, he supervised, along with Bishr al-Afshini, the governor of Tarsus and the Cilician border zone, another prisoner exchange on the Lamos River. In 918–919, Mu'nis campaigned against the rebellious ruler of Adharbayjan, the Sajid Yusuf ibn Abi'l-Saj, who withheld part of the taxes owed to Baghdad and had even seized provinces in northern Iran from the Samanids without the Caliph's approval. In his first campaign in 918, Yusuf initially withdrew before Mu'nis to his capital, Ardabil. After attempts at mediation with the Caliph by the vizier Ibn al-Furat failed, Yusuf confronted Mu'nis in a pitched battle before Ardabil, where Mu'nis was defeated. In the next year, however, Mu'nis defeated Yusuf in a second battle before Ardabil and took him as a prisoner to Baghdad. Yusuf remained captive in Baghdad for three years, while in the meantime, Yusuf's "ghulam" Subuk held power in Adharbayjan, having secured the Caliph's recognition. It was Mu'nis who was responsible for persuading al-Muqtadir to release Yusuf in 922 and restore him to his old position, this time as a servant of the Abbasid government. In 920–922, Mu'nis was instrumental in defeating a second Fatimid army sent to take Egypt. The Fatimids once again took Alexandria and occupied the Fayyum Oasis, but their fleet was sunk and Alexandria retaken, trapping Abu'l-Qasim in the Fayyum, from which he was able to escape only with heavy losses. In 923, he launched another raid into Byzantine territory, capturing a few forts and returning with much booty. At court, Mu'nis was an early and staunch opponent of Ibn al-Furat, and an ally of the latter's main rival, Ali ibn Isa al-Jarrah and his faction.