What is the point of the the Invocation mystery ?

Hello !

In a campaign, I'm playing a magus of house Tytalus, member of the Titanoï. Browsing the virtues known by the cult, I can't help, but I find the virtue "Invocation" quite lackluster. It is a major virtue, and it needs a lot of lab work to be used properly. Even then it give a bonus maxed by your Magic Theory to magical activities, provided you spend aditionnal time in the case of spellcasting.

Is there something I missed ? Or is this a really bad idea to initiate this virtue ?

Martoche.

Not really.

That depends on your idea of your character.

Typical HoH:S p.94f Tytalus Titanoi practice TMRE p.75ff Hermetic Theurgy summoning and controlling spiritual entities, in particular Titans and their offspring. As such, they can use every single bonus to spellcasting scores they can get, and are usually not concerned with adding some rounds to casting time: many of their strongest spells (see e. g. TMRE p.80f Invoke the Pact of (Daimon)) are Rituals anyway.
Such magi are not fast battle casters: even their bread and butter spells like TMRE p.79 Invoke the Spirit of (Spell) take extra time to instruct the summoned spirit. As you noticed, they spend a lot of time in the lab researching Names of Power, invocations, spells and codes in ancient lab texts, so their Magic Theory will usually get high over time.

Cheers

That being said, this is one of the canonical paths to Hermetic Therugy (as OneShot discusses), which is arguably some of the most powerful utility magic out there. Specifically, the MuVi version of "Summon the Spirit of (form)" - which, if you design your character correctly, pretty much lets you cast any MuVi spell at lvl 25 or below, without concentration checks. Sure, in order to do that you'll need to be able to design a spell for a lvl 50 spirit summon, and then get +50 penetration on that spirit (which is actually doable - AC to the spirit + ceremonial casting + props + sympathetic connections + a decent Penetration skill = not that hard to get over 100 on the roll.)

So basically, regardless of your speciality, Hermetic Therugy allows you to spont-cast your specialty at lvl 25 (with no penetration, really) formulaically, at the cost of taking an extra turn to do it. Some specialties won't benefit from this all that much (CrIg, for example, usually needs penetration), but for the most part it's a REALLY nice minor virtue to have. It's just that MuVi is the TeFo that probably benefits the most from spontaneous casting.

EDIT - that being said - yeah, the other virtues for this cult are kinda blah. I'd recommend talking with your GM to see if you can justify having the cult do some integration research, so that maybe some of them are already in their version of Hermetic Theory, and as such you can just spend a season or two reading tractiii to learn about it, rather than having to initiate. Or just combine one or two of the minor virtues into the major virtue, so you get more than one at a time.

Note, that Titanoi (HoH:S p.94f) typically already have a Major Magical Focus: Spirits applying to most of their TMRE p.78ff Hermetic Theurgy spells.
TMRE p.78 Invocation Magic comes on top of that, adding after some time easily another +10 to their Spell Casting Scores. It also beats the competing TMRE p.31 Major Hermetic Virtue Major Potent Magic hands down in versatility, and thus becomes a most useful Major Mystery Virtue for me.

Cheers

It's what I call a "penetration virtue". Basically, if you have no penetration issues, don't bother.
But if you regularly have issues making your spells connect, this is an excellent virtue. Yes, it requires some labwork - which is an excellent reason to invest in Magic Theory anyway.

However, unlike other "penetration virtues", Invocation can also help you cast powerful spells (usually rituals), that you might otherwise not be able to succesfully cast.

Please note that to get Invocation, you must already have Words of Power, which covers this specifically.
Hermetic Theurgy is not really the point of Invocation - what Invocation does, is allow you to apply Words of Power to anything you can find a name that covers.
Which means that with a large enough collection of Names, it's close to being Potent Magic (Everything), except you don't have to carry around a flea market's worth of trinkets, you just need to be able to speak the Names of those you Invoke.

Otherwise, I agree with the core of One Shot's response:

Though only in a cumbersome way: with TMRE p.76f Hermetic Theurgy and Names of Power alone, you need to tie the use of specific Names of Power forever to the invoke spell you invent, and limit the bonus from them to your Magic Theory Ability at invention time. Not quite the thing to suggest if the OP already found TMRE p.78 Invocation Magic lackluster, because it gives only

and requires

.

Cheers

Thanks for your answers !

I think I will wait for some time before initiating it then.