"I'll leave the strategy for capturing him in your capable hands. If he dies, it's a calculated risk I'm willing to take. If he survives, well, that's when my skills will become most useful."
((You guys lay out how you want this to go down... If you want to intercept him soon after she leaves the cave, or try and lure him into the cave somehow.))
"I would have thought that you'd need to go back to the cave system where Tria last was. But yes, certainly, Theraphosa will know of a good bit of cavern nearby. I've been mostly focused on the regio myself."
My note actually divide up the stats for which parts of Theraphosa are mundane and which qualities are not. Would her children be grog level Magic Might creatures? Or just mundane spiders? Keep in mind that she has the Difficult Underlings flaw, so they're probably talking spiders, at the very least. Hatched about 5 years ago (Winter, 1222)....
Okay.
Isen will round up theraphosa, tria, anyone else who wants to participate.
Thanks for coming, everyone.
We don't know our enemy's strengths. So we will try to capture him, killing him if that proves too difficult, and getting out of here alive should he be an elder magus doing grunt work.
The greatest difficulty in capturing him lies, first and foremost, in his eventual ability to translocate.
If he can't, it's fine. So let's assume he can.
If he knows the Leap of Homecoming, we'll probably fail, until we can incapacitate him before. Same thing if he knows Seven League Stride and was paranoid enough to take an arcane connection to a place outside the cavern before entering it. Otherwise, he'll need to rely on sight. And this is where getting him into a cavern can help us.
Thera. We'll need a cavern with a separate entry and exit. I will wait near the exit. Tria will enter, pass me, and flee. I will block the way with an Ice wall, layered with a magnitude 1 (cast without fatigue) Creo Imaginem spell to make sure he can't see through it. And I will wait, masked by a similar Imaginem spell.
Once he enters the cavern, you'll wait a little, and follow him. I need you to do two things. The first is to block the entry with your webs once he's gone, make sure he can't go out or see through it. If you could trap it so that rocks fall on him should he try to escape, it's fine. Make sure you can still exit easily and dissolve your webs should he prove too powerful for us. Then, follow him at a distance. Don't risk your life, save if you think you have a good shot at him. Viscaria tells me you might be able to enchant him. I doubt it, but you can try. Otherwise, use mundane attacks, and put your life first and foremost.
As for me, I'll first try to put him to sleep. I doubt this will work, and this robs me of the element of surprise, but I must try. Failing that, I will try to incacitate him.
Save that I have a hard time striking at a magus like that without him having breached the code first... Tria. How's your rego imaginem? Could you detach your image from your body, leave it inside the cave so as to "confront" him? If he then attacks you, he'll have clearly breached the code, in the spirit if not in the letter.
Well, it's probably me, but I see more her children as miniature magical versions that purely mundanes. I have some difficulties picturing her giving birth to purely mundane children.
=> I'd probably do them as lesser versions, probably riddled by some flaws (not immortal, need to eat) that would ensure they would not cover mythic europe in a few dozen years. So yeah, grog level characters 
Having an outburst of work, but it should be brief, I'll try to whip up something to propose you 
Theraphosa suggests, "Has anyone seen the enemy? If we could craft some likenesses of him, it would aid our attacks against him. I will make my early attack efforts focused on obtaining arcane connections, once we have seen the effect of my violins."
OOC: I just realized that Magic Creatures can also get points in Penetration, and that it would aid her Enchanting Music PENAID, and now I want to go back and adjust Thera's seasons to read that book. Which I'm not going to do, but damn, is she going to focus on Penetration someday.
Isen puts his hand to his chin, thinking
Good point. Tria, I guess you haven't seen him, that would be too much of a boon... I think we'll have to settle for blood. Wounding him should give you a potent arcane connection. Same thing if I wound him and you get hold of some sprayed blood.
OOC: Yes, Penetration is VERY helpful once you get some penetration multipliers, which usually aren't all that hard to get hold of. Even without it, you can easily get 5 points for your favorite attacks, which isn't negligible, especially for magical critters.
Johnatan: Doing as specified above.
The Creo Imaginem spells will be:
Blanket the Ice Wall: CrIm Base 1 (image that affects a single sense), +1 touch, +1 size, +2 sun duration = lvl 5. Isen Cr 19 + Im 6 + Sta 2 = 27
Hide the Magus: Isen will get close to a cavern's wall, and create the illusion of a wall before him, so as to hide from his adversary. Similar that the above. He needs a finesse roll for the illusion to be credible: 1d10=2 + Dex 1 + Finesse 6 = 9
With tria's accord (she'll have to lower her parma), he'll also bind her image and to an object:
ReIm Base 4 (Make an object appear (to 1 sense) to be attached to another object defined at the time of casting), + 1 touch, +1 Conc, +1 changing image, +1 moved image matches changes = lvl 20
Re 26 + Im 6 + Sta 2 + Rego Aura 10 = 44 + Dice 1d10=1, 1d10=5 = 54/2 = 27.
He'll have his talisman maintain the effect.
He'll rest 2 minutes, and do the same with Tria's voice: 1d10=9 (so it flies).
Assuming Tria can cast the following InIm spell
Base 1 (use sight at a distance), +4 Ac range, +1 Diameter = lvl 10.
The idea: she hold the object, do everything normally while holding it. But she leaves it (and her image, and her voice) in the cavern, using the InIm spell to see what happens here. So when her pursuer comes in, she can "confront" him. Hopefully, he'll let slip a thing or two that will help us.
Also, if he then attacks her, he breaches the code, and Isen will feel more at ease when striking at him.
I'm not really clear on what Tria is being asked to do...
Our plan of attack is outlined in the post above. Could you reference that and ask specific questions, or point to the parts where the uncertainty comes up? For example, the part where it says "Tria will enter, pass me, and flee." is pretty self explanatory, but maybe you're not clear where she's entering?
He is suggesting that we use Rego Imaginem to transfer her image to an object she can drop behind her as she exits through the fake wall, so that her tail will think she is still in the cave. She might also use InIm to observe and manipulate her species and interact with the tail.
"So let me get this straight. You think he will eventually come into the cave? I don't think that is a reasonable assumption. My ability to traverse through caves is not exactly a well kept secret. I mean, I don't blab it, but my House knows about it and our structure isn't such that we think about keeping secrets like this, normally." Tria adds her insight into the proposed plan.
(JL: Just in case I was not clear: What I want is draw him into a cave. That's all. Have you understood it? I'll assume you have, and he won't follow Tria into one)
Well, curse me for not being very knowledgeable about it, then, says Isen, frowning.
Since you suspect he wants to kill you and follows you, I'd had hoped that, if you appeared to seek shelter from the night, he'd follow you. Sadly, I was mistaken.
Yet, limiting his sight may be essential.
Tell me, should you engage in a ravine of sort, do you think he'd follow you? Has he done things like this before? What kind of terrain has he avoided?
I think we should keep the part where you move your species, if only to ensure your safety, but I'd much prefer ensuring he can't teleport by sight, should he be able to do it.
"I think he's been following me for the last few days. I think it's unlikely that he'd come into a cave where I am, because he doesn't know I'm still in the cave, or he might be concerned that I drag him to another cave. Like I said, I think they want to make this look like an accident. I seriously doubt any heavy magic will be brought to bear on my demise. Something where the sigil would be very subtle if existent at all or that they bring in a mundane assassin when they perceive I'm at my weakest. I have kept to well traveled roads. I have felt that it is best for protection, and it's also how their mundane agents travel.
She pauses, "I can try moving my species, I suppose." She doesn't seem to think that this will actually do very much.
((What wasn't clear was whether the planning was done, and now Tria is saying that pulling him into the cave is unlikely, given that they probably know about her ability to travel through caves. Of course that assumes that they know about that ability, but she thinks it is likely that they do know about it.))
Well, moving your species and voice has 3 purposes: Protect you from any harm, provide a target for the assassin, and, hopefully, learn something from him.
As I said, I am uncomfortable striking at someone that, as far as I know, has not breached the code yet. You suppose him to be an assassin, but he might be a dupe, made to follow and spy on what he was told to be a potential enemy of the order. As they say, better safe than sorry, and I'd feel better striking at him if I first saw him try to kill you.
And don't worry: Unless he tracks you through an Arcane connection, in which case I wonder why you ain't already dead, it should fool him just fine.
I understand you may feel that all this is overly complex. And it may be. If your tracker is a mundane, everything's simple. But I can't bet on it. We've got one chance, and one chance only, so I'm preparing for a magus.
Now, my concern is as follow: If he can translocate, any trap that doesn't incapacitate him instantly is doomed to fail. There are 2 ways for him to do that: Through sight, or to an Arcane connection.
We can bar the Arcane Connection for anything but The Leap of Homecoming or Seven League Stride, and, unless he's quite cautious, probably for the second spell. Should he flee via an Arcane Connection, though, there's nothing we can do, although this is very unlikely.
So let's concentrate on sight-based translocation. The only way to block it is to block his line of sight, thus my questions and my search for a suitable place.
The essence of the plan is "lure him into a trap and take him." We started with thinking about caves because of Thera and Tria's associations with them, but we're looking for any good location to do such a thing. Could we pick a suitable spot with a map and a Hunt roll?
Isen is getting more and more unnerved by this. Being so dependent on another, when he likes to do what he wants, how he wants it... He must suppress a tendancy to just throw up. This may be important.
"We could probably find a ravine of some sort. If he's interested in doing me in, he may be interested in following me into such an odd place. I think the cave is something he'd avoid going into."
Maps of the period were rare, and her location wasn't ideally chosen. She found a cave with an aura and a magic aligned regio, and was able to transport here.
(Fiona makes Theraphosa's pendant in 1226.2, but we still haven't determined the major side benefit)
"Well, then the question becomes how do we get a giant spider and a Ice mage somewhere that he can be lured to? I suppose that I could just wait inside the cave after she leaves and then follow the follower. Isen can wait and then follow the trail that I leave behind for him. The next night, we jump him."
Isen nods
This will do. We can keep the plan as it is, then, with one caveat. Theraphosa. Let's assume he flies. Once the trap is sprung, do you think you could spin webs over the ravine so as to avoid him escaping like that?
Well, we could leave the plan as it is. Since we know where he's going to be, I can wait while hidden behind a false wall and all. But you make me consider. Once we've found him, we could track him and ambush him at night, eventually gathering an AC... No. I'm not that good a hunter.
Unless you have a better idea, I still think ambushing him in a place of our chosing, where his abilities to escape will be limited, is probably the better thing to do.
Tria responds and stands, "Very well, I think there is a suitable spot about a day's journey from the cave. I'm about ready to go, if you are. Can everyone breath under water for a few minutes?"