Magi generally increase their power by studying in the laboratory. They can also can get a few points from adventuring experience. Also from being trained by another magus, but I am given to understand that training another magus has certain negative connotation, though not quite on the same scale as being another magus' lab assistant.
However, I am wondering what a magus would need to do in order to get (semi-)regularly trained by other magi? I understand that this sometimes happens in House Tremere, but what of non-Tremere magi?
Basically, be a mercenary magus and get paid in training.
What tasks would this mercenary magus be expected to do, so that his various employers would devote a season of their time to training him, in their sanctum?
A magus probably would only hire someone's help agreeing to pay with one season acting as a trainer or teacher (meaning, for him, wasting one season of his own time) if the mercenary's service saves him at least (and probably more) than one season's effort.
So just check the recent thread about Services, trade and business between magi. A mercenary magus would probably be someone who can do, with ease (or effort, if he really wants that training or teaching to happen) something of that list that his employer wants and that would cost him 2 or more seasons to achieve.
I envision Archmages as all having their own projects, which grow in difficulty and complexity as the years go by. Some parts of those projects can be done by grogs, other parts they need to do personally, but some will require a magus's touch but not necessarily their own. If they trust a younger magus, I imagine they may be happy to delegate that work to them in exchange for a season's teaching.
In my vision, such work would almost always match at least two elements from the following list:
A) Incredibly precise ("Invent this exact spell and enchant it into an item made of Cappadocian Oak. If you use Anatolian Oak instead, I will know and I will consider our deal broken.")
B) Bizarrely secretive ("Go to this address in Paris. You will find a ward on the back door. Dispel the ward, then leave. Don't ask why or whose house it is.")
C) Notably dangerous ("Of course the tomb is guarded by faeries and infested with the undead! If it wasn't, I could just get a grog to raid it, couldn't I?")
D) Require multiple seasons, probably at least 4 ("I could do this myself, but it would take a year. I'll give you a season of my time teaching if you do it for me.")
E) Require the use of Mystery abilities which the archmage doesn't have access to ("It's really very fortunate that you came to me; I've spent years looking for an assistant who knows The Avenue of the Spherical Mirror and the Station of the Microcosm.")
F) Will lead to real trouble if they know the Archmagus was involved ("Of course, if you're caught, I'm going to deny any involvement.")
These are my thoughts. Please let me know if they're useful!
I can't help wondering, has there been a significant change from ArM3 to ArM5 in this matter?
I have still not read, nor debated, as much ArM5 as I have ArM3, and I have always had a very distinct impression that accepting training and service would be admission of complete and utter inferiority, and virtually unheard of. Everything speaks against it. Having to forfeit protection under the code by working in a foreign sanctum. Broadcasting the superiority of the master, etc. In ArM5 I see some hints that it may actually happen often enough to speak of!?
In short, what is suggested is essentially apprenticeship. It is identical to the first (regular) apprenticeship, except for the stakes which are higher.
No point in adding to the already long list of suitable duties. Many things must be in place to make it worthwhile though. The training has to be so much better than self-study, that it is worth the high price that seasons of service would be. That means that both the master needs to be good, and the student has to be bad, but creative block goes a long way in explaining.
I'm not familiar with ArM3, but the only canonical cooperation/teaching stigma I'm aware of in ArM5 comes from assisting another magus in the lab. By doing so, the 'assistant' is declaring to the Order that he/she is inferior to the other magus (ArM5 p. 103), which is demeaning unless the primary magus is the assistant's parens. Neither learning spells from a teacher (ArM5 p. 95) nor learning from a teacher (ArM5 p. 164-165) mentions any kind of stigma for learning from a peer.
IMS, we've had similar-aged magi trade spell-teaching seasons using a neutral lab without stigma. We decided working in another's sanctum would still be bad, but otherwise it's just two peers learning from each other. We've also had an elder magus teach every member of the covenant a couple times, which actually made the students look better because they can say they trained under a (local) authority on Magic Theory. While it hasn't come up yet, one magus learning an Ability or Art from a peer would probably be handled without stigma. YSMV, of course.
A rich Covenant that asks for a season of service of their Magi each year may find itself hiring or hosting some other Magi with expertise they lack, and one of the member Magi could very well discharge this service obligation by teaching; a good teacher/writer magus's season might prove extremely attractive to such an itinerant magus. As well as access to the Covenant's library.
In Mystery Cults this magus-to-magus teaching may be perfectly normal, particularly if secrecy is paramount. Don't doubt the Bjornaer do this on the regular.
I have the impression the player base has mellowed on this point. Being taught by a noted expert on a subject doesn't seem like it's that humiliating. Bonisagus magi are expected to share, and teaching is a way of sharing. Cult members teach each other. Tremere magi could be called on to teach. Furthermore, a journeyman-level mage, four years out of Gauntlet, sneering at the prospect of being taught by an ancient archmage, expert in a field, seems incredibly arrogant; only a bit less so for one master of Subject A to ignore the benefit of learning from some elder mage, master of related Subject B.
However, forfeit immunity in another mage's sanctum is still a tradition, and I'd think there was a way to meet on a more level playing field, or at least to not bare your throat.
by taking instruction you acknowledge the teacher as your superior. This prevents magi from taking beginning magi with differing specialties and teaching each other relatively quickly from the PC base, but on the other hand acknowledging the superiority of a magus a century older than you with accolades throughout the order as to their accomplishments is just being realistic. The situation in mystery cults is similar- you do acknowledge the superiority of those whose rank or position within the cult is higher than your own.
Would this really be advantageous? Unless your beginning magi are designed for this purpose (with Teaching and/or good Com scores), you're looking at around 12-14 xp for two seasons of work - one for the teacher and one for the student. It seems like both magi would be better off reading middling books in the 8-10 xp range for two seasons rather than trading two seasons for teaching.
If such a magus is from House Bonisagus and contributes to it in a less creative manner (like a Trianoma, a Colens Arcanorum (HoH:TL p.10f) or such), The Durenmar library is always open to him (GotF p.55). Not so creative magi of other Houses would benefit greatly, if they have or find the vis to bribe their way into the library (GotF p.55). This can easily outclass serving an individual magus for instruction.
A magus joining a Mystery Cult does find Mystagogues and teachers there, if he faithfully fulfils the cult's demands. Some cults like The Mystic Fraternity of Samos (TMRE p.126ff) require, that their higher ranking members - many well known - form circles and teach new members.
Trying to shop around for Hermetic instruction with little strings attached as a true mercenary magus might have the same drawbacks a mercenary suffers compared to a knight: he does neither pledge nor receive loyalty, is expendable, and only gets called and rewarded if the knights available are not sufficient for the task.
There is the simple and general example of the ArM5 Longevity Ritual (ArM5 p.101). The better ones are typically made by a specialist - like TSE p.63f Xenias the Leper - assisted by the recipient who anyway needs to be present in the lab.
Indeed. That's new in ArM5. Longevity potions for others used to be penalised in ArM3-4, so that it took a very skilled vendor to get a significantly better potion than a typical magus could make for himself. I had forgotten why I had this impression of change, but this is of course one of the examples I have seen.
A second example is the mystery cults which is also new, where it is generally assumed that the initiate learns from a mystagogue. Although self-initiation is possible, it is harder, and if mysteries are guarded as secrets of the cult, it takes a lot of specialisation to invent own scripts.