My campaign calls for a mysterious magic object, a keystone of sorts, with a curse on it. The object itself will open a tomb in the Holy Land, and it is made by a very powerful, and very evil magus and infernalist. The Keystone will empower those who possesses it, twisting fate in their favor, but if they loose it, they will be doomed to suffer some horrible fate, unless they Keystone fulfills it's purpose first (which is to open the tomb). The backstory is somewhat long, so I won't get into that.
So, in the rules, how do I go about creating such an item. Can in fact the rules in RoP:Infernal be used to create magic items using the main rules? So could this item carry with it dark arts?
So, other suggestions on how to create this item using the rules in the game?
I won't comment on mechanics. I don't have my books with me.
I'm not sure if you're looking for suggestions on the curse, but here are a few:
Since the device is triggered by time, the curse may have to do with aging. The characters age unnaturally fast until the tomb is opened.
You might also have the curse have something to do with vices. The characters are each afflicted by one of the 7 vices (at random) with a trait of +3 until the tomb is opened. Until they get the curse lifted, the trait remains at +1.
The curse could also swing events in their favor if they're acting toward opening the tomb, but curse them unluckily if they're doing anythign but.
In RoP: Infernal, I'm thinking Malediction as the possible type of curses. Nasty accidents will happen to those who have owned it, but lost it before the tomb is opened. Like if the keystone itself "removes" any witnesses.
In my campaign, the characters' covenant is located on an island outside Brittany. They Keystone comes to them via a grog who've won it in a game from a crewman of a ship from a ship that just docked nearby. He senses something evil about the Keystone, and being loyal, he delivers it to the magi. The same night, the ship, moving on, is wrecked in a storm outside the island, and the grog dies in some horrible accident. This might get the magi suspicious, and they find that they have no choice but to find the what the Keystone opens.
And the Keystone will begin to "speak" to them, seducing them and have them to all manners of nasty stuff, kind of like a certain ring from my favorite book/movie.
Now, since the magi will no doubt research the object itself, I will have to set down the actual effects for it.
So they know about the tomb via the keystone itself? Having a cursed "talking" keystone would make me want to destroy it, not bring it to its destination to unleash an infernal horror to the universe (likely effect). And being a mage I might be proud enough to think that my magic abilities would be able to overcome the curse. Careful there
Besides, a keystone is rather more difficult to carry around than a ring, isn't it? Weighting a few hundred kilos et al. Wouldn't it be easier if you simply gave them a cursed talking shovel or a regular key instead of a keystone?
The Keystone is small, it's actually a missing missing piece of the tomb's outer wall, and could fit in the palm of your hand. The magus who removed it, a Hermetic Sorceror (RoP: Infernal) did so in the process of locking the tomb. Again, backstory is quite long.
So to break it down: we need a magic item that unleashes an effect on you if you loose it. It has other subtle effects too, and these are favorable.
Looking at page 103 of RoP: Infernal, I think I've found the answer. Lot's of nice stuff there. But can Maleficia-effects be used in magic items?
I would try to do it like this:
The stone has a single power: It increase the owners aging roll by one for every year he refuses to travell to the holy land. This way your characters have a reason to start the journey but may have the time to prepare and even research spells suited to a desert environment.
Adjected to this stone is some kind of demon who avoides direct interaction (DEO is in some troupes used frequently on strange beings...).
This demon somehow communicates the characters the following facts: The item was cursed when removed from the grave of XXX (Salomon, David,...) by an impious mage. The curse is inherited by all those owning it but may be broken once returned. This way the stone itself is not percieved as evil... When the item is given away or broken, the person dies shortly after and is will suffer in hell for ever.
Actually most of this is not true, but the demon sees after those giving the item away... As most characters will not give it a try, there is no need to imbue an effect to kill the person giving it away.
If the story about the grave involves something the character is longing for (ancient magic!!!), the will be little need to press the character too hard.
I don't have the book in front of me, but if memory serves the answer is no, because the maleficia are Rituals when combined with Hermetic magic. Although, one of them (Incantation/Effusion, I think) allows for enchanting items in its effect guidelines, so you can design the effect you want using the maleficia, and then design this other effect to hold it in the item.
If you don't want to do it that way, I'd suggest the sorcerer summoning and binding a demon to the object. Demons can do pretty much anything you want them to do, including duplicating maleficia with their powers and appearing as a normal magic item to non-Divine investigation.
But, can a magic item designed by a Chotonic (spelling?) Magus use the ranges and durations from RoP: Infernal in an invested item? Like the Curse (condition) duration?
Hm! I don't think it's specified, so I say go it! Makes perfect sense in context.