Oh I have a lot of material on Swain/LeBlanc and their connection with the Black Rose, from the 5 years of Journal of Justices plus League Judgements. When you're talking about the Black Rose though, you inadvertently involve the both of them.
Here's some additional knowledge about these two and the Black Rose:
Swain is an ex-Black Rose member!
From LeBlanc's League Judgement
"I have," she agreed with a smile; but there was only sadness in it. She stretched an arm across the table, clasping his scarred hand in hers. "But then, you already knew that. You knew it before you sold yourself."
Swain pressed a thorned onyx ring into her hand. "It is true. I have made sacrifices. But I made them for us. The Black Rose is yours, Matron, but I have become something greater." As if in agreement, the raven on his shoulder cawed. "The time has come. Join me in fellowship, and we can restore what was taken from us by Boram Darkwill."
She gazed at the ring, "You have forsaken your identity to gain Darkwill's trust. The rest will not be so eager."
"Perhaps. But there are other ways," Swain continued.
Now the following is basically a summary of what Swain and LeBlanc were up to for years, and this was chronicled in the Journal of Justice back when we had it. I'll try to be chronological.
During the Ionia versus Noxus grudge match (we're talking back when Innervating Locket was a thing), Swain couldn't be chosen as a champion for the IRL match. The in-lore reason is that he was being promoted and was attending a gala held in his honor in Noxus. LeBlanc was his date.
Perhaps just as curious as the circumstances of his promotion was Swain's choice of companionship for the evening, which caused quite a stir at the proceedings. On his arm all night was none other than the infamous (and notoriously reclusive) LeBlanc Emilia LeBlanc, who had not appeared in public for decades
The JoJ article goes on to say just her showing up and being in Swain's company, not only re-asserted the presence of the Black Rose, but also her and thus the organization's support for Swain in a very public manner.
A final interesting thing that another JoJ issue showed, was how it seemed the other Black Rose members didn't like working with Swain . In Volume 1 Issue 24 , a fake reader's letter was addressed to LeBlanc, written as follows:
“Beautiful lEblanc, Where hAve you been gRowing thosE rosebushes? Just Under a few Days aGo, whilE coMpeting in matchEs with you, i learned i waNted to Try my fingeRs at it. do you raisE your plants Close to nOxus or touRnament grounDs? Surely you Can not sUspect those Rumors of bIg Old Ugly ravenS Making fIne Garden protectors, tHey likely spliT the Soon as the winds raisE there wings highEr. But i hear kaLamanda hAs some riCh soil surely you Know how to nuRture yOur plants with that. pleaSe excuse the poor propEr puncTuality tHis yoRdle typEr device hAs a problem with shifTing unexpectedly, maybe you would consider accompanying me in garnishing a new one? we could conVerse further about rAising plants and maYbe if you would be iNclined in find a new outfit. ofcourse, accEpting it only as a gift from a friendly admirer, i would suggest against snake skin though it rubs irritatingly close.” – ZaineDraconis
Now there's a double meaning to this letter! First of all, interesting is the bit alluding that Swain ('big old ugly raven' that he is) will not be loyal to the Black Rose and 'protect' them, and that he would abandon them when he finally attains the position he wants (that of being the High General/Emperor). What it additionally sounds like is that LeBlanc chose to support Swain by herself, without consulting the other Black Rose members, and they're not happy.
The second meaning is the weird punctuation, which was actually decoded by IRL readers/players, which additionally reveals something about Vayne and her trying to find out more info on the Black Rose.
As for ZaineDraconis, no conclusive idea of who that is has ever came out, though I heard theories of it being Cassiopeia.
Now, for LeBlanc's reponse in the same issue:
“Don't ever garden uninformed, worry can quickly ensue! I think you should know a little or all you possibly can about anything you do. These tactics can save petty costs or prevent threats from ruining everything. There, in many instances, are a couple or several tricks to help factions who garden frequently, intent on consistency. Books on the subject say eliminating pests is paramount. Our gardeners focus on organization, seeds in place, but it is important we remember our roots: remain, above all else, informed.
Thank you for your thoughts. With plants, loyalty, or rather devotion, will yield best results. Be attentive, loving, and rewarded you will be. When we have trouble, we adhere to the rule: look at it all and decide which of your options works. Noxus thrives this way.”
This is much more cryptic, full of meaning and non-meaning in many ways. Basically, she's saying she knows what she's doing, and she's demanding 'loyalty and devotion' from the other members regardless of whether they agree with her methods or decisions or not. It still suggests an interesting division between her actions regarding supporting Swain, and the opinions of her own subordinates.
Finally, there's the most recent interaction between them. And I'm including this here because it actually does show an interesting shift in their 'relationship':
From the Sion remake promo page:
: "I haven't had the pleasure of your company for some time, Grand General".
: "You have my favor. That is enough".
: "And yet, I suspect you're here to seek the Black Rose's assistance once more".
: "The blood of the Jarvan IV Demacian prince. How much remains"?
: "After the last charade? Enough that you should be very mindful of how you use it. Whatever you intend had best be brief".
: "No chicanery this time; my need for subtlety is nearing its end. I must secure my position with bloodshed, and that requires a blunt instrument".
: "It sounds as if you have one in mind".
: "Let me show you".
So there's been a sort of...cooling of relations, so-to-speak, from how 'closely' they used to work together. For example, the 'charade' that LeBlanc mentions is that back in the Kalamanda/Dominion incident, she took the place of Jarvan IV and deliberately made it seem Jarvan provoked Swain/Noxus (this was originally hinted by a high-res version of the image where LeBlanc's face is reflected in Swains' breastplate instead of Jarvan IV when they were 'fighting').
Swain has not called on LeBlanc as often as before, perhaps even deliberately avoiding her and LeBlanc has noticed. He reassures her that he still 'favors' her, for now. She even mentions that apparently unlike other times, he's only approaching her for 'assistance from the Black Rose' specifically this time.
Furthermore, here's Swain's own thoughts on the whole matter with Sion and his resurrection with assistance from the Black Rose:
We've come full cirlce: a Grand General in need of a champion, the Black Rose seeking to wind its roots further into High Command, and a fallen warrior starved of battle.
So he clearly sees himself separate from the Black Rose now, and that he knows the Black Rose/LeBlanc want to influence and infiltrate High Command even more.
Does this suggest the warning from the Black Rose member back in Issue 24 was warranted? That Swain would attempt to distance himself from the Black Rose/LeBlanc the moment he got what he wanted?
TL;DR SUMMARY
Swain was a member of the Black Rose, he left to pursue another method of conquering Noxus and to possibly create a new identity for himself to trick Boram Darkwill into trusting him. LeBlanc decided to collude with Swain over how to conquer Noxus that was mutually beneficial for both of them. The other members didn't like associating with Swain (possibly because they thought he was a traitor since he left the Black Rose, although Swain keeping the club ring suggests he was still loyal to a degree). LeBlanc deliberately made a public appearance with Swain during his promotion gala just to make a point to the Noxian elites about whom the Black Rose's support was going to.
LeBlanc continues to help Swain in growing his support in Noxus, for example in the Kalamanda incident by deliberately creating a situation where Swain looked like he was defending Noxus' claim on Kalamanda, when she disguised herself as Jarvan IV and 'fought' Swain.
Post-attaining the Grand General position however, Swain and LeBlanc do not appear to be as 'close' as before, possibly showing Swain deliberately distancing himself from the Black Rose now that he doesn't really need them. He knows that LeBlanc/the Black Rose wants to gain even more influence over High Command, potentially noting her own attempts over him.
is not really positively involved in the Black Rose. Basically he's buddies with the Du Coteaus, who are very much anti-Swain and hence anti-Black Rose.
"COWARDS!!!"
is one of the black rose members
