I play 4th edition so have that in mind, I am not familiar with the rule changes made in 5th edition. Also this might have been covered in the forum before.
My general idea, or question, is; is it possible for a Magus to make them self into a Invested Item/Device. I have looked in the book and I could find nothing that would prohibit this. At the very least you should be able to make the bones magical, ans you are allowed to make only a part of a item magical. And bones are covered by the book (p. 83 in the "Material and Size Table").
Another thing that seem to indicate that is is allowed is the Longevity potion. They can be made into tattoos (p. 89), so in a sens the body of the magus can be made magical / house a magical effect.
So as I see it there is nothing stopping a magus from making them self into a Talisman (the more powerfull version of a Invested Item/Device in 4th edition).
Or am I missing something? Have this already been discussed, if so what was the broad strokes of the discussion / consensus?
And yes I realize that there might be some things / situations where being a magical item is not the best situation you can be in. =) But I think there is a big probability that even if you are a that other would not notice or if there notice think that it is some other magical item that makes it look like you are a item.
There'a a specific mystery, "Inscription on the Soul", which allows the body or spirit to be turned into a talisman (and which comes with a few minor additional bonuses in addition to the standard talisman ones). So probably not in general.
On a tangentially relevant note, Hermetic Projects has some rules for enchanting a live egg (so as to create a creature with custom powers, which requires a Minor Breakthrough to become possible. It's not clear to what extent the breakthrough is required because you're trying to enchant the entire animal (rather than just a tattoo, which as you noted before is possible), and to what extent it's because you're granting powers rather than a standard enchantment.
The problem is see with enchanting your bones is that you cant handle them, see them or touch them while enchanting them. While it is not stated that you need to do so in order to enchant an item, i think that would make it kind of difficult.
On the other hand, it is possible to enchant your tattoos, which should offer you some possibilities on enchanting yourself.
The bones is just the most extreme example. You could quite possibly just make your flesh magical. But if for some reason making the flesh magical was a issue then your bones would do fine.
Regarding touching and handling them. Well that would be easy, you just need a knife and make a cut down to the bone. Probably you need to apply a pain relief spell first. And after cast a regenerate flesh spell.
Or do you mean handling as in handling the bones in order to activate the enchantments? If that is a issue then just make the enchantments permanent. Thus eliminating the whole activate them problem =)
I meant touching them in order to enchant them. Altough that is a decision for your troupe, because you are ofc "touching" your bones all the time, but for me the enchanting process takes some working on the item.
Only problem i see with enchanting your flesh is that an enchanted item looses its enchantment when broken. Just physically mending it doesnt restore the enchantment. So your enchantment might break the next time you get hit with something sharp. Bones can break, too, but it doesnt happen as often.
A tattoo on the other hand might be safer if applied on a part of your skin that doesnt get hurt so often.
I have not read / found any part that would indicate a item breaking means it looses the enchantment (but I would agree that damaging a item would effect the enchantment). Is that from the 5th edition?
But I don´t see how enchanting your flesh/body and then being cut would affect that. Having a body part be cut of or a chunk of flesh on the other hand (or a bone breaking). That I would argue would effect the enchantment.
Well, you can enchant items made of bone. I actually considered this issue a while ago, and I didn't reach a conclusion because there was a point that I didn't find clairified in any of the books (as far as I remember, of course I could have overlooked them).
Ignoring the whole issue about if having the bones in your body count as "touching", my idea would be to extract a bone through a Rego Corpus spell, keep it "alive", and the wound unnaturally healed through non-ritual Creo Corpus spells through the duration of the enchanting, and then reattach it with a ritual Creo Corpus spell.
The thing is that the books aren't entirely clear on the issue about enchanting living things, or about enchanting things that are under the effect of an active spell.
If a player wants to develop the spells or ritually cast the sponts to take his ulna out of his arm for a season or more to enchant it then return it to his body, there is no way that I, as a story guide, am saying no.
I'd totally have something happen to the magus during the period that takes into account the complications of their condition (even if they're using a magically created temporary replacement) and of course they'll be warping, perhaps even beyond the long term effect warping during the enchantment. But this is a fun idea. To squash it under rules pedantry would be unconscionable.
One thing on a similar vein I had considered was if a Numerologist with Art of Memory could create a locus of his consulting text, solidify it with MuMe to enchant it and then put it back in his memory palace and be able to use its bonuses.
Wait a minute, Muto magic can't be made permanent. At most you'd have a lab text that lasts a year. MAYBE a Merintia magus could make an Until spell that is effectively a Geas... which is cool and flavorful come to think of it.
Jason72 was referring to an object that already exits in the magus's mind (in his or her memory palace Mysteries revised p25). The character is using muto mentem spells to take the book out of his or her head just long enough to enchant it, when the spell ends the book returns to its natural state - as a locus in the character's memory palace. A few overlapping moon duration spells should be sufficient.
There is the guideline in the core book about changing a mind into a physical object and the spell inmost companion. Also in the dream magic chapter of Mysteries revised we see examples of taking physical things out of dreams, even things in memory palaces. I think that materializing a thing from one's memory palace fits within normal hermetic limits without any additional virtue, (but it's not explicit).
I'm biased of course... I did an article for sub Rosa (issue 14) that detailed a Hibernian Verditius technique for replacing body-parts with artificial components, which could then be enchanted. I quite liked it as it was inspired by folklore tales/myths of powerful smiths being able to craft mechanical limbs that made their recipients whole again.
That's a little extreme, but it kind of works given the background.