Lucatiel is a very interesting character when you analyze her properly. Out of all the Souls games, she is the only person who is able to report to you the effects of becoming hollow. In DS1, it was a little mysterious when The Crestfallen Warrior, Laurentius, Nico and Vince go hollow; there seems to be no reason why (While Siegmeyer's hollowing can be explained thanks to the elaborations made in DS3, but that's besides the point). Lucatiel actually tells you what going hollow feels like, first is forgetting why you ever came to Drangleic in the first place, leaving a heavy question to dispel any reason to leave. Then, memories, oldest to most recent, begin to fade, including birthplace, names, loved ones, etc. Lastly, basic motor functions and core sentience are at risk, which is when the true "hollowing" takes place, leaving an empty husk. She tells us about her own hollowing, while others just up and leave, leaving their animated corpses to be found. That's why I like her as a character, she opens up to you. Too bad she sucks at fighting.