This probably should engender a hostile response from Stultus. At the very least, a back off, we will handle her, but dont engage her,,sincemthatsmwhat she wants. Tranquillina has a bit more latitude with how she treats Cumhachd in front of Stultus, but this veiled threat of bodily force for simply telling the truth? To his mater cara? I've decided that Cumhachd will ignore this, but authentically, Roberto is overstepping bounds. Yes, she said things in the worst possible way, but she isn't really saying anything that is untrue.
What? No veiled threat. Merely an offer of hospitality. These guys are cold, I am a fire guy. Trying to help. She misunderstands me. And I was trying to offer her a way to make amends and start over.
But perhaps he needs to work on his social grace, I wil agree 
Um. I really don't think that's appropriate for Stultus or the relationship between him and Cumhachd. Mind you, it probably will engender a hostile response, once I've had time to write it up, but not for any of the reasons you list.
I got a laugh out of it because I was thinking almost the same thing. " Oh! Your men are cold. One moment. ROBERTO!!"
How do you understand Beloved Rivals to be then? Because I can tell you that Stultus would know that Cumhachd views this as Roberto involving himself in a family matter. She would be so very disappointed if you didn't say anything while she was in earshot. He's obviously incapable of handling the Truth. His hypocrisy knows no bounds, etc, etc. If for some reason, the roles were reversed, Cumhachd would be sternly insisting on whomever to back off, and to leave you to her.
We are men of action, lies do not become us. Further, your character is a Flambeau of whom she knows much. Indeed, based on how she described several of the members of Mons Electi she knows a lot... Your dislike of Tytali is well known. So she knows that you'd love to find an excuse to skewer her or her retinue.
Cumhachd was the one who declared the rivalry, and for her it is very much "love as ownership": certainly for Stultus, quite possibly for Tranquillina as well.
The only problem with that is, Roberto's not a Tytalus. He is a Flambeau, an unlettered barbarian. He is a priori, by definition, incapable of handling the Truth. He doesn't know what the Beloved Rival relationship means. (Actually, as far as I know, no other PC in the covenant has yet, in-character, twigged to the true implications of Stultus calling Cumhachd Mater Cara. Marcus would know, but that's about it.)
If it was MARCUS saying it, Stultus would tear a strip off him, because Marcus should know better. Roberto does not. I see Beloved Rival extending to other Tytali, not to everyone else in the order.
I think Stultus standing up for Cumhachd in this instance would be seen as an insult to Cumhachd. It would imply that Cumhachd is incapable of defending herself; that she requires her student to defend her; that she must be shielded from conflict. (Incidentally, that's precisely why he might do it.)
I've always believed that Beloved Rivals are a reciprocal relationship.
I have a problem with your understanding of Beloved Rivals. Yes, she declared it, but, she would never have declared it unless you had provided enough signals to her that you would respond in kind. That means defending her when others get involved in the dispute with her, on your behalf. It also means that she has prevented others from interfering with you, if you only knew... It also means that while she has done some things for you (you don't think you got into Eboris entirely on your own merits, dear boy, do you?) you have done nothing in return for her. If it is a one sided relationship, the better flaw is Tormenting Master (and I'll drop her behind the scenes machinations that got you into Eboris).
I will stipulate that I haven't been as polite (in speech) to either Tranquillina or Stultus as I should have. I'll be correcting that in the future. We'll call this her way of expressing an apology for not being there for her filius and filia. She has been absent from your lives for too long... 
Oh, it absolutely is a reciprocal relationship. She's just the "dominant partner", so to speak. Me saying she declared it was merely a prequel to me explaining how I think she views the relationship, in terms of the post I quoted. I didn't mean to sound like it was entirely one-sided... it's merely that, in my view, it is slanted. It's not a relationship of equals.
Do you have a response to my thoughts about "Beloved Rival" being an internal Tytalus thing, that magi from other Houses are not really expected to follow, not being enlightened enough?
Actually, Beloved Rivals can only be equals. Someone who isn't your equal isn't worthy of being a Beloved Rival, IMO. You can't stand against her, then what good are you? There is no dominant partner in the relationship. Opportunities arise to be involved in the other's life as they may. The Beloved Rival is an acknowledgement of love, and a desire to always be there to never let the other not feel conflict. But it is only the Rival's right to inflict conflict upon their own behalf (agents might be an exception to this, when it comes down to competing agencies fighting each other as a proxy for the rivalry). In fact, if you wanted to say there was a dominant partner, you could say you were it, since neither of you engaged each other for many of the past years. Comments, about thinking she was challenged well enough, and you thought it best she be left to deal with her own problems, and the like would be outstanding.
Oh, it is most certainly an internal Tytalus thing, although there are rumors that Chumachd had, before Stultus, a Beloved Rival from outside of the House, but there's nothing really solid to back that up, though. Precisely because it as an internal thing, it is unwise to allow sodales or covenant mates get involved. Tranquillina is a special case. She really hasn't learned the lessons of the House (and you know this implicitly is why Cumhachd is so hard on her), and you would grant her a bit of latitude, if only because you and she had a common Mater, but there is a limit to what you should be willing to put up with from Tranquillina. A fine line between standing one's ground and taking what is her right, and being rude. Afterall, she, Eskil/Tranquillina, colluded with a Trianomae, who heretofore had never stolen an apprentice (she's the first ever to do it) to steal her away from her true and proper mistress.
Although, you have only heard Cumhachd speak nice things about Tria.
There's a lot of nuance here, I'm probably not communicating it well enough.
Okay, I see what you're getting at. It is not something that they would be expected to KNOW, but it is something that it is expected of ME to point out to them if they do not.
The interesting bit here, IMO, is that just as Cumhachd is a challenge for Tranquillina to overcome, Tranquillina is a challenge for Cumhachd. Stultus believes Cumhachd is TOO obsessed over Tranquillina, that she is TOO emotionally invested in her former apprentice, that as a result her judgment suffers. Therefore, that obsession is inhibiting Cumhachd's growth.
Exactly.
Perhaps, but that also depends on how he sees Tranquillina. She is also wracked by self-doubt over never having completed the Tytalus gauntlet. She's spent the last 30 years as the impetus to drive her work ethic[1] in the lab. It could very possibly be that Cumhachd has seen the poor child torment her self too much and is here to put a stop to it. Or at least put herself into a position to be accept all the accolades when Tranquillina acknowledges what she's been doing.
[1]See the very last paragraph.
I'll road map where this is going a bit. Until you came along, I didn't really have much behind Cumhachd, besides her being a Tormenting Tytalus I need to figure out how to put together. But two magi who share a common mater being part of the same covenant... It's a grand Tytalian plot. And that's not even then interesting part.
"You don't honestly think that you and Eskil ended up here by some, some... accident, do you? Do you?! Oh, my dear boy, you are here because I arranged for you to be here, and her too. You think Tria stole her from me? Well, she did, but that was my plan and design all along. Me! I am the one! I set the precedent for a Trianomae to steal an apprentice an apprentice. Do you realize what a gift that was? And she has done it again. And then again! How many apprentices found the right master because of me? If only other Trianomae had the courage to follow her lead. And my fingerprints are on every one of them." Cumhachd lays out the Grand Plan, waiting for Stultus to see the implications she's left unspoken.
Not to interrupt a fine discussion but how many warping points do we gain each year?
You're messing with my rhythm!
Well there is one from the LR, and that's it as far as automatic. Everything else comes from things done in play.
Sorry about that.
I thought it was 1 but was not sure. Updating some character sheets.
I didn't see the overt rudeness as being out of character. I see Cumhachd's way as being very mercurial, both carrot and stick, and using whichever facet is going to be most "beneficial" for Tranquillina in the moment. (There's a reason Tranquillina reacted so strongly to Bilera's ever-changing tone, don't you think? ) And you know, when people who were once very close but haven't seen each other in a while meet again, sometimes their first conversation is somewhat awkward and they find it hard to express that closeness for a bit? Maybe that's kind of what happened too. (Not that Tranquillina herself has any fondness she wants to express on her side! But still - one easily slips back into old roles....)
Stultus actually thought it was a bit out of character. Not that she was rude -- he expected that -- but that she was overtly and viciously rude. In my mind, she's usually a bit subtler than that.
Fair enough. Maybe she was legitimately embarrassed about having to ask for help with regards to the well-being of her retinue?
She wasn't vicious!
She was simply telling it like it is.
Fiona consorts with diabolists, well, one, really, but it's not by choice...
Alexei is opaque when it comes to politicking and intrigue.
Called Marcus a guard dog.
Korvin is jeopardizing his reputation and that of his House, such that it is, by taking on Abigail as his trainee.
Gerulf is a bit too new for her to know much about and properly describe, so she did the best she could. That should be rectified eventually.
I was having trouble coming up with a description for Roberto that would be suitably vile and substantively true. And I didn't do Isen, because Fixer hasn't said much around here lately. :-/
But she did say the whole lot of magi were suckling from the teat of Apollodorus. So, there is that. Something for everyone.
She's not like, you can't handle the truth, she's more so, you need to handle the truth. I'm telling you what it is. What everyone else out there is saying about you behind your back. "Well, that's what I heard, anyway." I'm thinking she's Shirley Maclaine's character from Postcards From the Edge.
Never saw the movie, but if her goal is to make people see and recognize the truth, that's a self-defeating tactic. Most people would have a really, REALLY hard time seeing past the insult to the underlying truth. That might actually be something Stultus thinks she needs to work on. 