Complex sentence: His signature weapon is the Mini-Slugger, a fortification based machine gun, which he is able to carry despite its weight, that he found during a battle with Khadorion forces, since then, no one has told him to put it back.
Split into simpler sentences: His signature weapon is the Mini-Slugger, a fortification based machine gun, which he is able to carry despite its weight. He found during a battle with Khadorion forces, and since then no one has told him to put it back.