I really appreciate how Lucy's complexity gets overlooked sometimes because she doesn't get as many spotlight moments as, say, Dazai or Chuuya. Her defining trait is a profound, almost painful loneliness forged from a lifetime of being used as a tool and isolated by her own ability. She built walls not out of malice, but survival. That's what makes her arc in the Guild so compelling—it's not about her being evil, but about someone who's never known genuine connection latching onto the first group that gave her a semblance of belonging, even if that group's motives were exploitative.
Her growth after joining the Agency is slower and quieter, which I think fits her perfectly. She's not suddenly bubbly and outgoing. It's in the small things: the hesitant trust, the reluctant lowering of her guard, the way she starts to perform small acts of care without expecting anything back. Her strength isn't flashy combat prowess; it's the immense courage it takes for someone with her history to choose to trust again. The fact that her ability, 'Anne of Abyssal Red,' is a literal isolation chamber she can trap people in, but also a refuge she herself can escape into, is such a brilliant metaphor for her entire character.
A lesser-written character would have been 'fixed' by friendship. Lucy isn't. She's still prickly, she's still defensive, she has moments of regression. That feels real. Her loyalty, once earned, becomes fierce and unwavering, but it's a loyalty that's been tempered by skepticism. She's learning to belong without losing herself, which is a far more interesting journey than just becoming 'nice.'