The unexpected Codex Inquisition has arrived. While I don't currently play any human force, I was intensely interested in just what the codex would contain. In particular, I was curious how it would work and whether it would be a standalone force or a quasi-supplement for Imperial armies.
To begin, considering it is priced lower than a supplement, there was only so much to be expected from the book. As was fairly widely predicted, while the army can technically stand alone (it says so), there really aren't the units available to do so. Namely, the codex features two named Inquisitors (not Eisenhorn, though he and many others are mentioned) and three generic inquisitors (who at their points with three wounds, definitely have potential) from the three main ordos.
Just some quick takeaways: the Condemnor Boltgun here, compared to the Adepta Sororitas, became much clearer, but also extremely nerfed. In the Inquisition book, a psyker only takes a perils would when it already suffers an unsaved wound from the condemnor boltgun.
The Inquisitorial detachment does not have to count as Primary or Allied detachments, and instead, can be fielded in addition to those. So, for example, you could have Space Marines with Sisters of Battle Allies and an Inquisitorial retinue consisting of 1-2 Inquisitors and up to 3 Henchmen units (Elites). Inquisitors are battle brothers with all imperial forces, Allies of Convenience with Eldar, and Desperate Allies with Tau and Dark Eldar. They can also treat the two detachments in an army differently. The example given in the book is that in a primary force of Space Marines, allied with Tau, the Inquisitorial detachment will treat the marines as Battle Bros, but the Tau as desperate allies.
As a standalone, the Inquisitorial army still is 1-2 HQ and 0-3 Elites, but Henchmen count as scoring.
One Inquisitor can be your warlord instead of an HQ from the primary detachment and roll on one of three tables based on their Ordo.
One of the three Inquisitorial Relics, the Tome of Vethric, is interesting. Depending on your opponent, the Inquisitor gains special rules for all Xenos detachments (prime or allied). Each special rule is a relatively useful trait for fighting that enemy. For example, when the bearer faces Tyranids, he will gain the Monster Hunter special rule. Against Tau/Eldar allied, he will gain Split Fire and Furious Charge.
I haven't had a time to read the Codex in much detail yet, but I'm honestly mainly looking forward to reading the fluff.