Much of this post will build on my previous post on the Order of the Green Hand. I'll try not to repeat too much, and I'll put a bit more history into this post than my previous posts.
The Order of the Green Hand was originally founded by a Sorcerer (think Carcosan Sorcerer, but with the ability to cast any spell as a ritual; we'll get to Sorcerers later in this series) who discovered the Ritual of the Green Hand and numerous low-level Magic-Users from the various Magical Academies who were disillusioned with the zero-sum culture, constant infighting and politics of the Academies. The Order, then, is based on the idea of cooperation and mutual aid. All of the Magical Academies found this idea dangerous both because it shook up their comfortable world and because they recognized that Magic-Users cooperating together, and with Sorcerers, would be much more powerful and effective than the Academies, divided as they were by petty squabbles. They hunted down as many of the early members of the Order as they could, coordinating their attacks on a single night of purging, known as the Night of Green and Red. Most members were killed, but some escaped; most that escaped lost their spell books and were only able, at a later date, to copy the spells they had memorized (and not used during their escape) onto new spell books. A very few members of the Order were able to abscond with a few higher level spells; to this day, the Order's spell books are skewed towards many low-level spells and few high level spells.
The Magical Academies continued to hunt the Order, citing the Order's connection to sorcery to the authorities and expending considerable political capital to convince them to ban the Order and eventually founding an order of Purgators to stamp the Order out of existence. The Order eventually found safe havens, however, in the good graces of kings, lords and city-states which did not have Magical Academies within their territory and desired reliable access to court mages, advice and magically capable agents. Eventually, the Order became established enough that the Academies no longer challenge it openly outside of their own cities (which the Order still has not been allowed to establish a presence in) and the Purgators have dwindled in number and their ranks are now filled with more Assassins than Paladins. The Order, as it has gained power, forged an alliance with the Assassin's Guild to combat the Purgators, who violate the Assassin's strict insistence on their own monopoly on assassination.
As described in my original post, members of the Order have access to many shared resources at the Order's many dormitories. One of these resources is the dormitory spell books. Whenever a member of the Order discovers or obtains a new spell, it is copied into the dormitory's two spell books. Every month the dormitories send one of their spell books on to the next dormitory in a set rotation and once the new spell book arrives any spells that one book has but the other does not are copied into the book that does not have them. In this way, the number of spells available to a member of the order is constantly, if slowly, growing. Mechanically, every month there are (1d6-4) new spells of (3d6-9)th level. (No new spells if either roll goes below 1.)
Despite the enmity between the Order and the Academies, the methodology of their practice of spell-casting is basically the same; after all, the founding Magic-Users of the Order all came from the Academies. The relative inexperience of the founding members was balanced out by their practice of mutual aid as well as the desperation of the early days of the Order, so members of the Order today are able to cast spells just as well as alumni of one of the Academies, save that they don't specialize in certain spells like the Academies do. Like graduates of an Academy, members of the Order must check against their Intelligence scores whenever attempting to learn a new spell; failure means that the spell may not be learned at the member's current level, but a new attempt may be made each level until the spell is successfully learned.
In the methodology of magic outside of casting spells, however, the Order owes much to the Sorcerers within its ranks. Ready help and teaching from Sorcerers enable Magic-Users of the Order to cast rituals of one half their caster level. In addition, members of the Order may copy spells they have not mastered into their spell books and may cast them as rituals, something alumni of the Academies are not able to do. In addition, members of the Order benefit from Sorcerous training in the crafting of magic items; mechanically, they craft them as if they are one level higher than they actually are and as if the laboratory they use is one increment more valuable than it actually is.
Higher-level members of the Order often take administrative positions within the Order, helping to run a dormitory, manufacturing magic items and protecting and advancing the Order through diplomatic and political means. At least one of these members will always be on duty in each dormitory to give help and advice to any members that need it, though they will be most knowledgable about magic and local politics and generally ignorant about other subjects. (If a PC is a member of the Order, when the PC established a stronghold, it will be, or will at least include, a dormitory.)
Each dormitory possesses a modest library and laboratory, serviceable but nothing like the libraries of the Academies. Tables for determining the their value, as well as the mechanical benefits of staff of the dormitory, will be forthcoming.
Finally, it should be noted that Sorcery, that is, the casting of rituals by those without the capability to memorize spells, and especially the casting of rituals which cannot be memorized as spells, has never lost its stigma. The continued presence of Sorcerers within the Order is a secret, even if it is suspected by many. Low-level Magic-Users in the Order are not told of the presence of Sorcerers within the Order and Sorcerers of all levels are aided in passing as Magic-Users. Once a Magic-User has reached fourth level (also the level where one no longer must surrender magic items to the Order, and when the hands turn green), the Magic-User is told of the membership of Sorcerers and introduced to the dormitory's book of sorcery, which contains all the rituals the Order possesses (mechanically, three kinds of rituals will be in the book of sorcery: rituals for which the Order does not have the spell, since rituals may be cast from spells, but spells cannot be cast from rituals as the ritual "write-up" contains less information than the spells do; rituals that may not be cast as spells at all, such as Carcosan rituals; and, finally, the ritual write-ups for all the spells that the Order has, including all the information necessary to rebuild actual spells, as back-up).
When first given this information – the membership of Sorcerers, the reality of Cthuloid beings, the possession of horrible Carcosan rituals by the Order – the Magic-User must roll at or under Wisdom or go catatonic (and unplayable) for d100 days; this same risk is repeated the first time the Magic-User attempts to study a Carcosan ritual (so it is in the PC's best interest to study one at the first opportunity so that this risk doesn't have to be run when time is of the essence).