Cassia Build Guide (Rogue Trader)
entity:cassia is the strongest companion in Rogue Trader, and the build is not subtle. Spec her as a entity:grand-strategist entity:officer, pour every point into Fellowship, and let her entity:navigator powers do the rest. Two entity:lidless-stares will kill pretty much any random encounter, and on Unfair difficulty she turns brutal fights into formalities.
Build: fb43eb90c0abWhy Cassia Tops Every Tier List
Cassia is the consensus number one companion, and it is not close. She joins in Chapter 1, which means she is online before most of the roster, and she stays best-in-slot through the final act. Her edge comes from two stacked engines that share a single scaling stat. The Officer chassis gives her party-wide control of the action economy, while her Navigator heritage gives her the Lidless Stare, a warp-eye power that hits a wide area for enormous damage and control. Both engines key off Fellowship, so every point you invest pulls double duty.
The short version: she glances at the enemy line and half of it falls over. Stack two Lidless Stares in a turn and most random encounters end before your carries take a shot. That is why she trivializes Unfair, the hardest difficulty in the game.
Fixed Archetype: Officer
Cassia starts locked into the Officer archetype. You cannot reclass her at Tier 1, and you would not want to. Officer is the support backbone of any party, built around buffing allies and bending the turn order in your favor. entity:voice-of-command marks a buff target, and entity:bring-it-down grants that marked ally an extra attack that ignores cover and doubles effective range. Land it on a Voice of Command target and the attack also ignores dodge with a damage floor that scales off her Fellowship bonus.
On Cassia, that support engine sits on top of her Navigator nuke. She can buff an ally, hand out a bonus attack, and then drop a Lidless Stare of her own. No other companion folds that much value into one turn.
The Tier-2 Choice: Grand Strategist vs Master Tactician
At Tier 2 you pick how Cassia spends her turns. Both paths are strong. The decision comes down to whether you want her to amplify the party or carry the damage herself.
Grand Strategist (support)
This is the default and the pick that earns her the top tier. Grand Strategist adds zone buffs that blanket your formation, an unconditional first turn so Cassia always acts before the enemy, and an extra turn handed to a psyker in your party. That last point matters: if you are also running entity:idira, Grand Strategist Cassia effectively gives your wizard a free action every round. Pair her with a hard-hitting carry and she frontloads an entire round of damage before the opposition moves.
Master Tactician (damage)
entity:master-tactician turns Cassia into a personal nuke. It converts the party's high mid-game and late-game momentum into a large personal damage buff and group attacks, so her own Lidless Stares hit even harder. Take this when you already have another Officer covering the support role (entity:jae is the obvious partner) and you want Cassia leaning fully into damage. It is the aggressive line, and it is excellent, but for most parties Grand Strategist gives more total value because it lifts everyone at once.
Either way, both Tier-2 paths benefit from the same Fellowship investment, so you are never punished for committing to the build early.
The Real Engine: Navigator Lidless Stare
The Officer kit is the reason Cassia is great. What pushes her past every other companion is the Navigator side. Cassia is a Navigator of the Navis Nobilite, and her warp-eye line, the Lidless Stare, delivers massive area damage and control that no archetype can match. Open the third eye and an entire cluster of enemies takes the hit at once.
The math that defines her ceiling: two Lidless Stares will kill pretty much any random encounter. You spend her turn opening the warp-eye, the screen lights up, and the trash fight is over. Against bosses and elite packs she still chunks the field and softens everything for your carries. Because the power scales off Fellowship, the same stat that powers her Officer buffs also powers her nukes, so a single-minded Fellowship build sharpens both halves of her kit at the same time.
Stat Priority: Fellowship Is Everything
Fellowship is the one stat that matters for Cassia. It scales her Officer abilities, the Bring It Down damage floor, and her Navigator power bonuses, all from the same pool. There is no split to manage and no second stat fighting for points. Push Fellowship as high as it will go at every level, grab Willpower as a distant secondary for resolve and warp resistance, and ignore the rest. A focused Fellowship Cassia is stronger than a hedged one in every situation that comes up.
This single-stat scaling is part of why she is so easy to build correctly. Many companions punish a misallocated point. Cassia just wants Fellowship, and the build stays online the moment you commit to it.
Recommended Build
Lock the path early and do not waver. Origin and heritage are fixed by the character. Take Officer, then pick Grand Strategist at Tier 2 for the support build that headlines this guide, or Master Tactician if you already field a second Officer and want Cassia as a damage carry. Stack Fellowship every level. Keep Lidless Stare and the Navigator line maxed as your primary offense, and use Voice of Command plus Bring It Down to launch your hardest carry into the enemy before they can respond.
Run her with a dedicated DPS companion and the loop is clean: Cassia buffs, hands out a bonus attack, opens the warp-eye, and the fight is already half won.
Where Cassia Fits in Your Party
Cassia is the first name on any optimized roster. She slots beside a ranged carry like entity:argenta and a damage psyker like Idira, where her Grand Strategist extra-turn-for-a-psyker line turns Idira into a double-acting threat. If you want to push the Officer engine further, run a second Officer in Jae and double the action-economy abuse, freeing Cassia to swing toward Master Tactician.
For the full party picture, see the companion tier list and the wider builds hub. For the Officer mechanics that drive her support kit, the officer build guide breaks down the Voice of Command and Bring It Down loop in detail.
Build her around Fellowship, give her the warp-eye, and Cassia will carry your dynasty from Chapter 1 to the throne.