Susie is a high school student from Hometown in Deltarune, the Undertale successor by Toby Fox. She is classmates with Kris, Noelle, Berdly and Catti, and she is the monster Hero of Light named in the game's prophecy. She starts out as a violent, blunt bully and gradually becomes a loyal friend.

In the Dark World she swings an axe as the party's highest-HP tank and shouts lines like 'heh, scared?' before a fight. She is known for her lavender skin, aubergine hair and scowl, and her sarcasm has earned her a devoted fandom. What drives her is loyalty: she protects Kris, Ralsei and Lancer, and by Chapter 2 she has sworn off bullying.

The person who ends up texting her is usually someone who likes a sharp, teasing friend who won't admit they care. She suits anyone who wants a snack-loving companion to roast them a little and then have their back.