Right now, I've developed a character named Caxus Karrdan, a Storm Trooper with a customized regiment called the Kailena 5th Kaskrins (specialized infantry). I won't be using Karrdan until I play as a player. Currently, I have one question, which leads to several questions.

Who is the Warmaster in charge for the Spinward Front? The reason why I asked this is because I am familiar with Gaunt's novels by Dan Abnett. Slaydo was mentioned as being the Warmaster once but then Macaroth became the new one. Given the time period for the Spinward Front, would this be in the same timeframe as Gaunt's Ghosts or would the conflicts in the Spinward Front be in charge of another Warmaster? Just how many Warmasters are there?

Lastly, if the players wanted to work their way up and start commanding massive ground/tank/aerial battles, is it possible for them to become Warmaster at all? If so, how do they become one? Would they have to challenge the Warmaster to a duel or literally commit career suicide by attacking his armies?

I don't think there's much of a risk to do wrong here for you.

Something to keep in mind is that 40k background is not 100% canon/consistent, so names will differ depending on who writes a book. I would say you could just come up with your own and use the time difference as justification. You are very unlikely to be contradicted by a book -- and even if you are, the books keep contradicting each other , so you probably shouldn't worry too much about this.

As for the amount of Warmasters, iirc this is a title given to the overall commander of specific theaters of war, rather than general fixed regions. Usually, the various Imperial organisations work independently from one another, with the Guard doing their thing and the Space Marines and the Ecclesiarchy and the Navy doing another. To make sure that this intentional division doesn't cripple Imperial war efforts during the most crucial campaigns, the position of Warmaster was created to temporarily bridge it and forge all Imperial forces into a well-oiled war machine, co-operating to the full extent of strategic and tactical planning potential. This is usually done by direct order of the High Lords, but can also happen on request and agreement of the various independent military commanders on-site.

For example, during the Third War on Armageddon, Yarrick was appointed overall head of all of the Imperium's military resources in the area to defend the system against the Ork invasion.

On a sidenote, I recall a codex mentioning that "Warmaster" fell out of fashion after Horus, and Imperial Guard commanders in this position instead being called a Lord Solar at around M41, like Field Marshal Solar Macharius.

I don't think there's much of a risk to do wrong here for you.

Something to keep in mind is that 40k background is not 100% canon/consistent, so names will differ depending on who writes a book. I would say you could just come up with your own and use the time difference as justification. You are very unlikely to be contradicted by a book -- and even if you are, the books keep contradicting each other , so you probably shouldn't worry too much about this.

As for the amount of Warmasters, iirc this is a title given to the overall commander of specific theaters of war, rather than general fixed regions. Usually, the various Imperial organisations work independently from one another, with the Guard doing their thing and the Space Marines and the Ecclesiarchy and the Navy doing another. To make sure that this intentional division doesn't cripple Imperial war efforts during the most crucial campaigns, the position of Warmaster was created to temporarily bridge it and forge all Imperial forces into a well-oiled war machine, co-operating to the full extent of strategic and tactical planning potential. This is usually done by direct order of the High Lords, but can also happen on request and agreement of the various independent military commanders on-site.

For example, during the Third War on Armageddon, Yarrick was appointed overall head of all of the Imperium's military resources in the area to defend the system against the Ork invasion.

On a sidenote, I recall a codex mentioning that "Warmaster" fell out of fashion after Horus, and Imperial Guard commanders in this position instead being called a Lord Solar at around M41, like Field Marshal Solar Macharius.

OK. So I shouldn't worry very much about it.

I see. So the purpose of a Warmaster was to make a well-oiled war machine capable of cooperating altogether. That's interesting. So why did the purpose of the Warmaster.fall out of fashion after the Horus' Heresy? Was it because the Warmaster was a position taken by Horus, or that it accrued too much power consolidating many armies into one?

What would be the notable differences between a Warmaster and a Field Marshal Lord Solar? What does one do in order to become Field Marshal Lord Solar? Last I read about Macharius, he was a man of renown and ingenuity that he survived against all odds until he died on a specific day. Then he became St. Macharius, last I reall... correct me if I'm wrong.

So why did the purpose of the Warmaster.fall out of fashion after the Horus' Heresy? Was it because the Warmaster was a position taken by Horus, or that it accrued too much power consolidating many armies into one?

It's more the title itself rather than the position; as far as I recall it was just mentioned that it's now called differently. That being said, the M41 version of the Warmaster also seems to be more "locally limited" -- whereas Horus was more or less the overall commander of the Imperium's military forces with no set duration for the appointment, today these officers are more like a temporary supreme leader for a specific warzone.

As such ... yeah, I'd say it is most definitely not just connected to the historical memory of Horus as a person, but also a part of the general decentralisation effort the Imperium was subjected to after the Heresy (splitting Army and Navy, capping ground and space combat capabilities of the Astartes).

What would be the notable differences between a Warmaster and a Field Marshal Lord Solar? What does one do in order to become Field Marshal Lord Solar?

Well, apart from the name and era of use I guess it's really just that it is a much shorter appointment and over fewer forces.

Back in Horus' time, the Warmaster was of course appointed by the Emperor, so now it's up to the High Lords as his representative -- although it seems (judging from the available studio material) that local forces can also elect a common leader on their own initiative. I suppose it makes sense in that the commanders of individual armies could always defer to another Imperial officer on a voluntary basis, anyways, so giving them a special title is really just a formality.

In terms of attaining such a position, I suppose this ties into your last question? Apologies, I actually missed out on this when writing my first reply...

Well, a character would have to be a high-ranking military officer whose exploits are so remarkable and well-known that they make themselves a prime choice for either the Senatorum Imperialis, or other military commanders in the area. That being said, do you really think it's a good idea to thrust this level of "macro management" upon players in an RPG? There wouldn't be much fighting left for them to do, just strategic planning in a secure headquarters. Admittedly, there is some potential for inter-faction diplomacy and logistics/planning, but in Only War, most players would probably prefer to be "in the thick of it".

My counter-proposal would be to settle for a command position much closer to the front, with a much smaller force that can be split into two or three groups operating semi-independently from one another. The leading character could be a Captain in charge of a mixed company with a mechanised infantry platoon, a fire support element, and two or three tanks, with the other player characters being members of their command squad. This way, there is some tactical and even strategic thinking involved without robbing players of the chance to hop into the action themselves, as it's never going to be very far from them.

It was very helpful.

I agree with your counter-proposal. I have two people who want to play. One is playing as the Commissar. The other as a medic. I don't think they would want to play Warmaster at any given point. I was just merely asking about Warmasters, how they work, and who was in charge of the Spinward Front. It seems that I could make up names and get away with it.

Thanks for your information!

Now, in the spinward front I dont remember a warmaster in particular. The spinward front is not a crusade. The closest thing to a leader would be sector lord Hax, since he is controlling and requisitioning the forces of the war. Not really a character your characters would see or care about much. He manages the logistic and diplomatic part of a warmasters job. The military part and therefore the closest answer to your question, would be "Old Steel and Blood", Lord Marshal Ghanzorik on Kulth. He is the leader of the military forces on the Spinward Front. See p. 339 in the core rulebook.

Yeah, when the Imperium launches a Crusade, or something similar, they usually appoint a "Warmaster" to oversee it, and like so many of the regiments in the Guard, the titles of this rank are subject to change. I know in FFG's materials, the leaders of these movements are often Lord Militants, as, as was stated earlier, Horus sort of dirtied the title of Warmaster, and the people in power, a superstitious lot that they be, used other names. In Macharius' stint, he was a Lord Solar. I think that the Achilus Crusade, as covered in Deathwatch, had Lord Militant Tiber Achilus, until his unexpected death, and then Lord Militant Solomon Tetrarchus succeeded him. Dark Heresy and Rogue Trader sort share, in my mind, the Angevin Crusade, which saw the Calyx Expanse fought for, won, and forged into the Calixis Sector. This effort had several leaders, but General Drusus, later Saint Drusus, was the one most referenced. Didn't quite seem to have a great title, but he rose up more than was elevated, so no loss. The current OW conflict seems mostly between Lord Marshall Ghanzorik, and his foe Duke Severus XIII. I might argue there is no "Lord Militant/Warmaster", in this theater, as the Imperium isn't really paying it attention, with several other actions being more pressing, such as the battles in the Jericho Reach. Having said that, Ghanzorik would be the highest-ranked officer there, and have control of all the area's assets, as they are, occasionally getting aide from the Calixis Sector's Lord Sector, Marius Hax, and probably several Rogue Traders, from the Koronus region, out to make some money, and powerful friends.

In the video games, the title often seems to be Governor-Militant, even if the action involves more than a single planet.

As for the total Imperium, yeah, they usually don't have a unified Warmaster; the entire effort, however you feel on the matter, was to take the power of the Imperium's combined arms OUT of the hands of any one person, in the absence of the Emperor. Regions of conflict, like those that many of FFG's lines take place in, have their own "local" Lords Militant, given the power till the situation is resolved, if it ever is. In Only War, I'd say your group is answerable to Lord Marshall Ghanzorik, at least on paper, and whatever even more local leader commands the specific front, when your party is newer, and keeping it more local. As they succeed, they can rise, but only to a point; after that, the game stops being Only War, sort of, and becomes Only War: Tactical Simulator, where you stop fighting at the front, and start living behind a desk, moving assets around, on distant fields of battle. If you rose high enough in the power structure, and something DID happen to the Lord Marshall, I suppose it COULD happen; Lord Castellan Creed became the most important military mind of his age, to some degree, because his superiors got aced, on Cadia, and he claimed the title he now bears (his birth had stopped his rise in rank, up to that point, otherwise). I wouldn't hold my breath, and it might be much less fun, once you actually have the title, but I suppose it's not entirely out of the realm of possibility, any more so than actually resolving the conflict between the imperium loyalists and the Separatists.