The first major narrative expansion for Warhammer 40,000: Rogue Trader arrives this month. Titled Lex Imperialis, it adds a new companion, a new faction, and a full story arc built around the Adeptus Arbites. Owlcat has chosen not to expand the galactic scale of the original campaign, but to deepen it, focusing on the legal and judicial spine of the Imperium, and what happens when that system is twisted beyond repair.
Set within the Koronus Expanse, Lex Imperialis introduces a chain of investigations that pull the Lord Captain’s crew into the enforcement arm of Imperial law. This is not the same kind of violence you saw in the main campaign. The Arbites don’t simply shoot problems. They document them. They prosecute. They judge. Then they kill. That shift in tone gives the expansion a sharper edge.
The core of the expansion is built around Solomorne Anthar, an Arbites officer assigned to your retinue. He does not care about your lineage or your Warrant. He cares about the law, and he follows it with mechanical precision. Solomorne is not a warm companion. His role is to measure you against a code you were never meant to follow. He questions your every move, tracks your deviations, and responds to your actions with either strict loyalty or quiet condemnation. His arc is not about friendship. It is about trust.
The missions in Lex Imperialis unfold across a self-contained cluster within the Expanse. The player investigates legal breakdowns, corrupted planetary governance, and suppressed archives of forbidden precedent. The goal is not conquest or trade. It is to expose, and in some cases, to sentence. You are forced to act within or against Imperial law, and the outcomes reshape relationships, planetary status, and faction alignment. Some decisions may lead to executions. Others to uprisings. The Arbites do not leave grey areas. They create order through force, and they expect you to do the same.
Mechanically, the expansion brings new systems into play. Judgement protocols give you access to Arbites-specific tactics in both conversation and combat. Verdicts can be applied to enemies mid-fight, changing their behaviour or weakening their morale. These options are limited and situational, but effective when used correctly. The writing reflects the procedural tone of Arbites culture, formal, concise, and heavy with legal scripture.
The environments match that mood. You’ll visit a courthouse built into a cathedral, a penal moon used for political dissidents, and a data vault so heavily redacted its own staff don’t know what they protect. These locations strip away luxury and excess. The glamour of Rogue Trader life is replaced with silence, discipline, and surveillance.
The story runs around fifteen hours, depending on approach. Completionists will find hidden case files and obscure doctrine citations that unlock unique decisions. The endings tie back into the main campaign, and may influence how later content reacts to your leadership. Solomorne will stay on board after the arc concludes, carrying his judgement into future storylines.
This kind of DLC is rare in the 40K catalogue. It doesn’t add units or maps. It adds perspective. It turns the spotlight inward. Lex Imperialis forces players to confront the structure of the Imperium, not just its enemies. It makes you play by someone else’s rules. And it asks what happens when you start believing them.
