I have no idea who Wally Purling is in this story. However, if we assume it's a typical Christmas story, Wally Purling could be the protagonist. He could be an ordinary person who has an extraordinary Christmas adventure, or he could be a symbol of the Christmas spirit, spreading joy and kindness during the holiday season. But this is just speculation without knowing the actual story.
Wally and Kuki are likely characters in a particular fictional universe. They could be from a TV show, a video game, or a comic. Without more context, it's hard to say exactly who they are, but they are the focus of the fanfiction, which means fans are interested in exploring their relationship, be it friendship, romance, or some other kind of connection.
One idea could be that Boromir is on a quest in Wally World. He thinks it's a strange new land full of unknown magic. Caitlyn, who is already familiar with Wally World, becomes his guide. Along the way, they encounter a group of mischievous kids who are causing trouble in the store. Boromir tries to use his combat skills to stop them in a non - violent way, while Caitlyn uses her charm to talk some sense into them.
Well, it could be an adventure story. Boromir, a character from 'Lord of the Rings', and Caitlyn from another realm (assuming) meet in Wally World. Maybe they team up to solve a mystery there. Boromir's warrior skills and Caitlyn's unique abilities could combine to face challenges like a strange creature that has been causing chaos in Wally World.
Often, the other members of the Young Justice team are involved. Artemis is frequently included. She might be the one trying to rescue Wally or be involved in the events that led to his being trapped. Robin also shows up a lot. He could be using his detective skills to figure out how to free Wally.
Wally could be developed by showing his growth in character. For example, if he was a bit cocky before, he could return more humble and with a deeper understanding of the world. This change could be a result of his experiences while he was away.
Wally could use his super speed to be there for the reader instantly whenever they're feeling the urge to self - harm. His presence alone might be a deterrent.