As far I can tell, Erioch is under Commander Mordigael , but what then?
How many Captains serve under him?

A Deathwatch Captain is usually placed in charge of several Kill-teams and given guidance on broad objectives by the Watch Commander .

And how many kill-teams serve under each captain?

How many marines are accomodated inside the Fortress?

Hundreds? Thousands?

I think it's left unclear deliberately. Were I to hazard a guess, though, I'd say two to four captains, each with three to five kill-teams of four to ten marines. So, somewhere between two captains with 24 marines under them and four captains with two hundred marines under them. Something like:

Mordigael

-Capt A

-KT 1, 5

-KT 2, 6

-KT 3, 5

-Capt B

-KT 1, 7

-KT 2, 10

-Capt C

-KT 1, 4

-KT 2, 7

-KT 3, 7

-KT 4, 5

This is coloured by my perspective of the Deathwatch being a small, elite group scattered across the Imperium. A larger, more traditionally sized detachment might look like this:

Mordigael

-Capt A

-KT 1, 9

-KT 2, 10

-KT 3, 7

-KT 4, 8

-KT 5, 10

-KT 6, 6

-Capt B

-KT 1, 7

-KT 2, 10

-KT 3, 10

-KT 4, 7

-KT 5, 9

-Capt C

-KT 1, 6

-KT 2, 8

-KT 3, 7

-KT 4, 5

There's much more Watch Captains, just counting the official ones, I think.

Also, the Librarians are not part of the Kill-Teams but form a cadre under the Watch Commander. Probably the same with the Master of the Forge. And then there is Chamber of Vigilance. And the Inquisition. And the DW Keepers. And the Dreadnoughts.

It's not simple.

Alex

There's much more Watch Captains, just counting the official ones, I think.

Also, the Librarians are not part of the Kill-Teams but form a cadre under the Watch Commander. Probably the same with the Master of the Forge. And then there is Chamber of Vigilance. And the Inquisition. And the DW Keepers. And the Dreadnoughts.

It's not simple.

Alex

True, but not all of them are necessarily based out of Erioch. The ones identified as being associated with specific salients are probably 'forward deployed' along with their teams.

Hm. I'd always had an image of the Jericho Reach being in the back of beyond, middle of nowhere, posterior-end of the rimward galaxy. The only reason that the IG is here is because Warp Gate, and the only reason the Deathwatch are here is because they never left.

I also had this impression of the Watch Station and the other resources nearby being large and having the resources to house and sustain a very large Deathwatch presence, but that it was all heavily underutilized, with something like just a station-keeping presence here, because while the greater Imperium contracted, the Deathwatch never left. Something like a Black Templar chapter keep orbiting a forgotten rock somewhere with a Castellan in charge of the keep- and some chapter serfs keeping him company, that's it.

If the Deathwatch presence in the area is on the scale of multiple codex companies in strength, I think my impression of the area was way off. This is what I get for skimming the fluff.

I like my "NORAD-on-the-frontier" interpretation better, but that's just me.

I think by the year 817 the Jericho Reach has become one of the hotspots in the Imperium. That said, there are usually only between 100 and 200 Marines present at one time. Depending on how fast the rotation is there are a few or many more across the Reach.

Alex

I thought the Deathwatch had a codex chapter structure? They even have scouts...just not rookie scouts. Kill teams are made up of specialists though, so they wouldn't have Scout, Devastator, Tactical and Assault squads. Though I imagine Deathwatch is 1000 Astartes.

So a captain per company, with 10 companies, with 10 squads each. The Watch Commander might count as the captain of the First Company, or he could be outside of the normal structure.

No. Kill-teams are very much organised as required for the mission - there's definitely no formal company structure.

Equally, the Deathwatch doesn't maintain scout squads, but sometimes a kill-team will deploy in scout armour, just as sometimes they will deploy in terminator plate.

I once tried to catalogue the marines in the books. I found the Master of Vigilance, 5 other Watch-Captains, 1 Chaplain, 3 Apothecaries (1 is also one of the Watch-Captains and 1 is a lone Kill Marine), an Epistolary (it is, however, stated that most Deathwatch Librarians are Lexicaniums), and 2 Forge-Masters. One of the Watch Stations has 40 Battle Brothers assigned to it but most have a single kill team. Some Watch stations have a single Battle Brother or none at all, being entirely automated. There are supposed to be many more Watch Stations than are illustrated on the map.

Off hand, I recollect reading that a few score marines are at Erioch at any given time, though it has the facilities to house an entire chapter.

While kill teams might be customized for a mission, efficient deployment demands that multiple kill teams deploy from a single voidship and kill teams are chosen from those 12-20 battle brothers.

Given these numbers it would appear that Erioch is home base to at least 200 marines and quite possibly 1000. And these are still stretched ridiculously thin covering the hundreds of thousands of systems that are located in the Jericho Reach. Keep in mind that the galactic disk here is approximately 1000 light years thick, and that wouldn't include all the halo stars. It's easy to forget that 3rd dimension on the maps.

It doesn't seem unreasonable that the Ordo Xenos has requisitioned an entire chapter worth of marines. The Ordo Malleus has a chapter dedicated to its service. Of course, the Ordo Xenos has a lot of other places to cover besides just the Jericho Reach. This alone leads me to believe the 200 figure the most accurate, and that's assuming the Jericho Reach is of utmost importance in the galactic scheme of things. Given that the Deathwatch maintained a presence here for 5000 years while the Imperium wasn't present, it seems that's also not an unreasonable assumption.

Given the numbers I already quoted, this seems to me a likely OB for Erioch. Let's put the "officers" at about 20% of the total. The US army is a bit above 10% with the special forces receiving a higher percentage, so I'll go with 20% or 40 of the 200 total. If each Watch-Captain has 3-5 kill teams of 3-5 members each, it would take 10-15 Watch-Captains to command the Deathwatch of Jericho Reach. If we split the remaining specialists equally, that would mean approximately 8-10 apothecaries, 8-10 tech-marines, and 8-10 librarians, give or take 1-2 each. That leaves about 50-55 marines of each specialty. These would deploy from approximately 12-20 voidships with a handful of voidships in reserve, another handful undergoing maintenance, plus a couple kill-ships docked and ready.

As mentioned, Erioch has significantly less than 200 Astartes on-board at any given time unless unusual circumstances apply. Page 328/329.

Alex

Yes Alex, but how many does the organization support in the Jericho Reach?

I wonder if even Mordigael knows.

I guess significantly less than chapter-strength. if every 100th marine is fit for the deathwatch, we have 10,000 across the galaxy.

Personally, I think between 200 and 300 is sufficient with numbers being ramped up recently by Mordigael as the Jericho Reeach is set to become one of the hotspots of the galaxy.

Alex

So, in other words, you agree with my figures.

I am also looking into making a dramatis personae of all the listed Deathwatch marines in the Jericho Reach. I only made up one Watch Captain in my campaign so far, and he died last night in a heroic sacrifice that saw the destruction of a hive ship. So now we can get back to the ones in the book.