so. the thing about Illario and Lucanis.
I don't have the screenshots but somewhere in Lucanis' mind, you hear Illario's voice saying "If I was in charge, you wouldn't have to do this anymore." as far as I can tell, all the other lines in his memories are from the game, but this one is from The Wigmaker Job. the story that took place over a year (probably more) prior to the events of the game. it's referring to a scene where Lucanis comes back from their contract, injured, and Illario, worried about his cousin, says that Lucanis wouldn't have to do Caterina's bidding anymore if Illario was First Talon. so now we know Lucanis still thinks about that conversation, even though it happened so long ago.
two other things about The Wigmaker Job: 1) Illario is a lot different in it and in some ways he seems more competent than the Illario we get in veilguard; and 2) we see Zara Renata at the end, and she already has Lucanis in her sights. depending on how much time passed between that contract and Lucanis' kidnapping, she could've been setting this up for months to years.
in the concept art/storyboard frames that were recently released, Zara is hardcore giving siren in the first image and it almost looks like she's straight up controlling Illario via blood magic in the second (imo)
now imagine if Zara was looking into Lucanis, started with the people closest to him, found Illario, and said all the right things. imagine she said he should be First Talon, Caterina never loved him, Lucanis doesn't believe in him and is secretly just tolerating him, he can save Antiva from the Antaam (or whoever else), he can lead the Crows to their long-awaited unification and make them even stronger, he's the smartest prettiest most super special boy in the whole wide world, etc. (if you give this man an ounce of praise and he actually believes it, he will crumble, I know it.)
now imagine Zara, having successfully sunk her claws into Illario - Lucanis Dellamorte's cousin, the only person closer to the Demon of Vyrantium than the First Talon herself - manages to convince him to let her kill Lucanis. he doesn't have to do it himself so there's less guilt. there's no way Caterina would make him First Talon if Lucanis was alive. and then Illario would be in a position to protect his beloved Antiva because if there's one thing the Antivan Crows are, it's patriots. I think Zara played Illario like a fucking fiddle and the game was just really bad at showing us that. I think when her spirit says "he fooled us both," she means he fooled her by being less of a coward than she thought and straight up killing her.
and maybe this is the Illario apologist in me, but I also think he realized the whole thing was a doomed plan after he was defeated. I mean, he shows up to the final battle to help, at risk of his own life. maybe he's trying to atone, maybe not, but still - he is there, and he sounds more like the Illario we see in The Wigmaker Job than whatever we got through the rest of the game. with his quippy little "was that suitably self-important?" line, he's closer to himself than he was this whole time, and that makes me wonder if maybe he wasn't fully Illario. maybe that was grief and guilt and a shaky sense of self and Zara's manipulation and the feeling of losing his grip on the power he never quite had to begin with, all bundled up into a new, bitter, resentful man. I think he was used like a pawn in Zara's chess game, and that doesn't take away from his agency in this situation or lessen the blow of his betrayal, but it does make it easier for me to swallow the fact that the Obvious Traitor Illario I was immediately skeptical of in-game is not the Illario I immediately loved after one scene in Tevinter Nights where he shaves a single hair because it was uneven with the rest of his five o clock shadow.
I think ultimately, Illario realized Lucanis would forgive him anyway. I think it's because he realized he would forgive Lucanis too.