After Grima travelled back in time, Loustica’s memories were mixed up and caused amnesia. She wakes up in the field, near the place where her previous-self was waiting for Chrom to show up in the attacked village.
She doesn’t remember anything much, not even her name. She only knows it when she glances at the cover of the only diary she’s saved from her mother “To Loustica”. After saving the village, Chrom recruit Loustica. As she is lost and doesn’t seem to remember anything, she accepts to join them.
Loustica gets accepted by the other members quickly. Lissa already spends a lot of time with her, which makes Maribelle a bit jealous. Miriel is a bit sceptical about Lou, as she recognizes Grima’s designs on her coat. Stahl adores Lou and sees her as a little sister, even if none knows her real age. Frederick soon stop thinking she could be a threat after eating her cooking (she’s an amazing cook haha Gaius loves her food too *especially candies uWu). She often trains with Chrom & Vaike to enjoy their rivalry and learn a few moves.
Lou has a lot of “nightmares”, which are in fact her other self memories. She wakes up a lot during the night and wanders around the castle court. She meets Chrom often there. That’s how they got closer.
After a few night chat and fight, Chrom and Lou were slowly falling in love but none of them could confess, being too shy. With the help of the other shepherds, organizing “unplanned events” (the infamous bath scenes * yes I like to imagine it’s maybe Stahl or Lissa who led them to meet bathing to make them closer as they were tired to see them being so obviously in love but too dumb and scared to confess it XD), they grew even closer and eventually kissed. (Insert shocked emoji here)
Chrom was mad and depressed by this event. He didn’t even show up anymore. He knew it wasn’t Loustica’s tactics fault but he needed a culprit: both Gangrel and Lou were somehow. Or at least, that’s what Loustica thought. She thought she was guilty for what happened. So she started to avoid him. Give him space. Chrom never saw it that way. He wanted her to come back by his side. To comfort him like she always does. To be the energetic woman he saw awake at impossible hours, not even tired... She still tried her best to ease his troubled mind and give her all to plan Gangrel’s death.
Lou let Chrom do the final attack to kill Gangrel, feeling like this would be a sweet revenge for him, a way to mourn his sister. And was quite happy to kill the Mad King and showed a little dark side of him. But after all, he was still the dork he used to be.
They officiallized their relationship, which was already a few months old now, and got married soon after those events. Loustica was very scared of how the people of Ylisse would react, as a simple commoner who also occurred to be amnesiac, but they were happy to see a new couple leading their country. They planned a nice public wedding a few months after the war, to let the people fully accept the time of changes Emmeryn and Gangrel deaths led the continent to. After their wedding, they quickly got Lucina for their greatest pleasure. The world was finally back to peace, at least for now...