Lol yeah I actually went over Calus’s lack of military focus very extensively in the post. Those alien weapons (and other tech) that were stored on the athenaeum world’s weren’t lost to time because Calus had them under frequent study and maintainment with overseers who knew their functions. But since Ghaul took over Calus has lost contact with the overseers that were loyal to him, so he has no idea what condition they’re in