It takes as long as the spring only because they weren't looking. They can stretch the oath that far, they can be disinterested in knowing - but now they know, and so there it is. Elwing of Sirion is twenty-three. Half-man, so fully grown. Sirion is a city of refugees. Elves and Men and, since there are Men, children. Elwing herself has infant children.
They debate whether to send messengers. Debating is allowed, even protracted debating. The Oath, these days, is loud in their minds, and louder when they're pushing it like this, but they drag out the debate for a few months. Messengers will probably be shot on sight. The last time Elwing of Sirion received news of the House of Fëanor it would have been the news that her brothers, twins, aged seven, had not survived the sack of Menegroth.
They send messengers anyway. The messengers are shot on sight. They have good armor, Fëanorian armor, and return home injured but not lethally. Maglor's songs no longer stitch them together. War makes you worse at healing. Maglor's songs are more powerful than ever - he can knock back a wave of approaching enemies, he can make a blade's next touch deadly, he can make them faster and more impervious to danger, but he can no longer do healing.
Maedhros, when he thinks about this, thinks that perhaps there needs to be part of you that is not broken for healing spells to draw on. Or perhaps the Enemy is amused to strip that away first. Perhaps the Enemy finds it suited to the theme as the Oath tugs and yanks and twists them into violence against the lands they once defended and the peoples they once sheltered.
They send messengers to Sirion again. The messengers deliver a plea for the Silmaril, an offer of anything at all in exchange. The messengers do not return at all.
The Enemy is many many hundreds of miles from here but at night Maedhros can hear him in his head. Is it so implausible that I really let you go? the Enemy likes saying. You serve me better free than you ever would have willingly.
The Oath allows them to work slowly. They begin planning the sack of the refugee camp even more slowly than the Oath allows, so slowly that its currents are constantly tugging at them. Any slower and the currents would erode all the things they care about which are not the Oath, and it would be a disaster to go to Sirion once they've been stripped of their capacity to care about anything that is not the Silmaril. So they do not hold out forever. But they work as slowly as they can.
"Specific enough that there's no chance I look away for a second at some point and you're far away finding someone else to get to rescind your orders, general enough that I'm not constraining you from thinking about escape - if I give my word not to escape, that only constrains my actions, but if I give my word not to consider escape, I change my mind itself. Are you the same?"
"Orders can make me think about something but cannot make me not think about something, or want something, or believe something. Why does your word do that?" Fucked up alternate universe gracewings? "I can't fly all that fast, I couldn't be out of earshot that quickly."
The fortress is not glorious, but it is imposing, and it has thick walls and is very very safe. There are people milling anxiously around the ramparts. He explains as they approach. I don't know what she is. I do not think she is of Arda. Don't read her mind or at least don't indicate you've done so.
She doesn't comment on the architecture. She just flutters along, keeping pace with him.
"The temperature's fine. I don't know if you have anything that would fit me," she is after all five feet tall and winged, "but this dress should hold up for a while longer. I could use more food. Plants are better, I think mort- I think some people eat non-plants."
"I have some questions. Answer truthfully and completely. If I say something like 'would you do this?' does that count? Or does it need to be more direct? If I ask you 'is there information you're withholding from me that I'd care about', do you have to use your best model of what I'd care about, can you rationalize? or change what I care about by suddenly doing something I care about significantly more?"
Twitch. "If you say 'would you do this' and don't specify under what conditions it leaves me partly free to imagine conditions on my own but you couldn't accidentally let me to say I'd do something I'd never do. With that phrasing I could use my current model of what you care about, I wouldn't have to think hard about making sure it was good, but I couldn't deliberately worsen my model by anything other than carelessness; I could do anything I wasn't otherwise forbidden to do in the hopes of adjusting my model but I wouldn't have a very long window to do it in before I had to answer."
"Yes, but how depends on what I'd think about your interests if I knew more about them."
Are you trying to figure out a way to trick me into some kind of mistake that makes me vulnerable to you? If so, what have you thought of? If having a warning before I ask your thoughts reduces your distress, you can always delay answering questions like that for a few minutes."
She takes a breath. She thinks for a moment. "Mutual vassalization is possible and if it were in place I'd be less afraid of you because vassals can't hurt their masters, although not by very much because plenty of things don't count as 'hurting'. If anybody mentioned your name I'd listen and remember it but I don't know yet what a good opportunity to learn it would look like. I'm currently free to speak and enforce orders if I obtain any vassals, of whom I presently have none at all, and I can also put my ears out if I get my hands on tools, which would make it prohibitively difficult to control me with orders, although my existing orders would stand and it wouldn't make me any more physically imposing. If you're under an oath like you described that means I have to think about this entire situation in terms of it being your master and thus mine at one remove and that affects how decent a master I can expect you to be on the general spectrum of people who keep slaves. It seems unlikely that you're a good source of unbiased information on someone who you've nicknamed 'the Enemy'."
"You may not give anyone any orders. Do orders have to be spoken? Giving them telepathically doesn't count? If you can't give orders, what changes if you learn someone's name, do you have other forms of power over them?" He isn't willing to stop her from putting her ears out. "Mutual vassalization is not acceptable to me but I am more than willing to give my word not to 'hurt' you if by that you mean physical violence. Are there other commitments that would make this situation less harmful to you without putting my people at risk?"
"Orders can be written if the vassal watches the master write it out but not at any degree of temporal remove. I don't know if telepathy counts but it probably does. If I can't enforce orders then the only thing someone being my vassal changes is whether they can hurt me or not and whether we can feed each other without adding new claims on the fed party. I - I don't want to be touched. Or ordered to hurt myself or anyone else. Or deprived of sleep. Or addressed by name even if you make me give my name which doesn't give you anything you don't already have unless you want to turn me over to another fairy, food works fine for nonfairies, are you sure you're not mortals you said the Enemy was going to kill everyone? If you're going to try to use me for any mental work more complicated than answering basic questions like this I will function better if I have time to - draw. If anybody ever finds a gate to Fairyland you probably won't let me go and get a cutting from my tree, will you."
"I will not touch you, or let anyone touch you, or order you to hurt yourself." He does not promise not to order her to hurt other people. There is a Silmaril, there is an Oath, they are moving towards Sirion as slowly as they can but they are headed there. "Or deprive you of sleep, or address you by name. You can draw. We don't have much paper but you can certainly use it. I cannot think why I wouldn't let you go and get a cutting from your tree, is there a reason I ought to hesitate to do that?"
"The gate might not be anywhere near it. I'd be away a long time finding it and bringing the cutting back and if there was a loophole in my orders I'd have time to find it and if you gave me a self-incapacitating contingency for that case I'd be hard to collect."
He stands. A bit unsteadily.