Editing Deathwatch (section)

==Organisation and Chapter Strength==
Another point of contention is how the Deathwatch is organised and how many marines they actually have.

The original fluff barely made any reference to how the Deathwatch was organised aside from being an ad-hoc arrangement of temporary squads and fortresses under the command of the Inquisition. In the Beast Arises, Koorland set that the Deathwatch be set to "chapter strength" back in M32, and appointed a single '''Watch Commander''' to oversee strategic aspects while taking his orders from the Inquisition. Admittedly, even the Watch Commander himself had no idea what the position entailed.

By M40 in the codex and contemporary fluff, Koorland's singular position of "Watch Commander" doesn't seem to exist and command is decentralised to the Watch Commanders of their respective fortresses and surrounding domains, making them roughly analogous to Chapter Masters. These new fortress commanders are usually '''Watch Masters''' but the codex implies this may not always be the case. ''(Interestingly, the new "Watch Master" role has been amalgamated with the old RPG rank of '''Watch Keeper''' who was one of the few permanent Deathwatch staff members and carried the same '''Clavis''' that Watch Masters now do)'' Whether the Masters have any higher authority above them is not made clear, depending on how much influence you think the Inquisition actually has over them.

Despite nominally being referred to as a chapter, the issue of "chapter strength" also seems to have been ignored, though this depends on how large you assume the "average" Kill Teams to be. For example: kill team Cassius was 11 strong, while kill team Artemis was 7 ''(himself as Captain plus 6)''.

A traditional Fortress such as '''Talassa Prime''' has been shown to have five companies of four kill-teams plus a '''Watch Captain'''. So there is probably somewhere between 21 - 41 marines per company, making 105 - 205 marines per Fortress, plus a dedicated command staff including a Librarius, Chaplaincy and any attached Dreadnoughts for around 9 - 10 members, plus an armoury of indeterminate size to maintain the fortress's vehicles, though a conservative estimate would be 3 more techmarines given the size of the other departments, especially considering the huge redundancy of experience spread through the kill teams themselves, which can compose of their own techmarines, librarians, chaplains and Apothecaries. All in all this puts a watch fortress at somewhere between 119 - 219 space marines. 
The Deathwatch tie-in novel shows around 200 members mustering at fortress '''Furor Shield''', though this was a joint action including watch teams from nearby jurisdictions, but probably remains a good estimation of roughly how large a bulked out fortress can be.

Across the Imperium there are four "primary" fortresses which probably have either significant strategic value or play host to unique facilities ''(Talasa Prime is said to be a major training facility)'' plus fourteen other regular fortresses, which are all said to generally follow the same core structure, so the concentrated bulk of the chapter would be anywhere between '''2142 - 3166''' Deathwatch Marines, much higher than "Chapter Strength", assuming all of the Fortresses are equivalent in strength to the primary ones.

The final number is also complicated by the 40+ smaller Watch Stations which house anything between squad or two all the way up to a full blown company! Though it is not made clear whether or not those small stations fall under the purview of the closest Fortress and being assigned squads from there, or if they have their own discrete commands, otherwise that would add about another 200 - 1640 to their roster. Nor does it account for any Deathwatch Marines on detached duties (Kill-Marines) that appear in the RPG but are not mentioned in the codex unless you count those units which can be deployed in squad sizes of 1.

In addition, the 8th Edition Deathwatch Codex mentions that Roboute Guilliman assigned "multiple chapters" worth of Primaris Marines to the Deathwatch. While its quite possible that this hasn't increased their overall numbers if they took grievous casualties due to the Great Rift/Blackness, this alone implies that the Deathwatch are far bigger than any chapter.

Given the possible final numbers anywhere between around 2100 - 4800 marines, assuming the Deathwatch maintains itself at full strength all of the time, and that all Watch Fortresses are equal in strength.

If that seems like a huge amount, remember that would imply that each chapter of the thousand or so in the Imperium are donating only about two to five marines at any given time. But given the number of repeat chapters represented in Talasa Prime ''alone'', added to the fact that apparently hundreds of chapters are risking dishonour by actually requesting their battle brothers return to their parent chapter, this unusually high number may not be an unfair estimation and may even be a lowball considering permanent members seconded from Chapters completely or [[Blackshield]]s who cut all ties with their former Chapter before joining (due to any number of reasons, being loyalists hailing from traitor Chapters, exiles or other personal reasons etc.).