My one physical roleplaying game (RPG) acquisition in March 2025 is Emperor’s Arsenal for Marc Miller’s Traveller (T4). The Traveller roleplaying game (RPG) has multiple versions and editions and the primary late-1990s version was Marc Miller’s Traveller or Traveller 4, aka T4. Published by Imperium Games under license from Marc Miller’s FarFuture Enterprises, the core game mechanism changed from the classic 2d6 to a nd6 (with the occasional half-d6) die roll. For that reason alone many people expressed “displeasure” with T4. While I generally agree the core game mechanism changes in T4 were not necessarily the easiest to understand—much less use in play—one aspect of T4 I really enjoy is the “setting reset.” T4 takes place in Milieu 0, that is, at the early founding days of the Third Imperium. As such, the average tech level is what I call “upper middle tech” in the Traveller universe. It is also an era where the core of the Third Imperium was expanding control across Charted Space which makes for much different adventuring potential as compared to the default setting of the later well-established Third Imperium a thousand years later.
Emperor’s Arsenal is written as though in-universe under the name Carnak’s Surface Weapons. The softcover book is really a listing of weapons arranged by Tech Levels; think from spears to very futuristic energy weapons. Weapon entries in Emperor’s Arsenal give Damage / Tech Level / Range / Shots / Mass or Volume / and Cost when appropriate. Today this data would be in an online wiki or the like but “back in the day” a book such as this was “luxurious” though with only a bit of some color in the form of Chris Foss artwork on the cover. The interior black & white artwork predates today’s AI-generated artwork and provides a bit of some character for the book that helps immerse players into the setting.
There are other interesting pieces like a discussion of Imperial Procurement Practices (in reality some hidden rules for procuring weapons) as well as new combat rules and special topics.
If you are a player of T4 is Emperor’s Arsenal worth the investment? If you are part of a player group where combat is central to your adventures then the answer likely is yes. Even if your group does not play T4 and maybe another version of Traveller—or most any RPG with a need for weapons—then Emperor’s Arsenal may be a good sourcebook that can be ported into your setting with little conversion effort needed. My copy was a used bookstore find but digital versions are also available for around $10 or less.
Feature image courtesy dreamstimes.com
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Rocky Mountain Navy Gamer 
Emperor’s Arsenal had some great stuff in it . I think the chapter of additional rules from page 7 is unsurpassed in all published canon for bringing a bit more crunch to combat. For example, the rules on using personal scale weapons against starships (and vice versa) on page 11 are so elegant and yet CT-MT-TNE had floundered about trying to manage such combat. Likewise the rules for torpedoes.