What convinced Lucian wasn't, ultimately, that Lianelle couldn't remember her past. Sure, it was suspicious how all of her connections to anyone besides May had been cut or weakened, but that was only enough to push Lianelle so far. What convinced him that May was mind controlling his friend was Lianelle's lack of interest in being anywhere but by May's side. Lianelle didn't do that for anyone. She loved Katia with an intensity Lucian had hardly seen in any marriage, but she'd only visit Quiteria for a week at a time - never staying unless it was urgently required. When armies had been raised to fight the Magyar Lianelle had been there, but even then she'd ride off alone often, returning with news about how one village or another was now free. Seeing her relegated to a bodyguard and lover of someone she'd just met, with no apparent intention to ever leave, was... wrong. It wasn't Lianelle.
And so, this is how Lucian finds himself digging a hole in an unremarkable forest in west Austria. Well, digging several holes - the landscape's changed enough in the last 1200 years that it's difficult to locate the exact spot where he and his men, victorious but weary, buried the Magyar's artifacts that they could not understand the purpose of.
"The Luciens don't match in every respect, mine keeps weirding out Lifeline." (Pet pet.) "But that seems arguably different from Lianelle having changed over time."
"I'm not denying she's changed over time! Probably she has, it's been centuries! I'm saying I didn't do it!"
"I'm pretty sure that even if I lived centuries I wouldn't be happy about staying with one person all the time and not being able to go on adventures on my own."
"I tried to figure out how to put her missing memories back but the magic user interface wouldn't play ball. I don't know why, I was introduced to this magic system only recently and all the magic people I've met besides Lianelle suck and she's not really a nerd about it."
"Um. Is it possible that the memories won't go because she's not the same person who lived in the past and knew Lucian?"
Apparently his early work in identifying individuals extends well to this.
"Yeah, Lucian knew a different person."
"...I don't find that a satisfying answer. You can have your sword back when you're departing my house."
"... I don't actually expect it to make a difference in any fight, but okay."
She leans on May and tears up a bit.
"Um, can you resurrect the original Lianelle?"
"I probably can but she's presumably going to want - her - wife, who also might want people, and - I'm leaning on knowably limited chains when I'm triaging espers -"