Sumí, a lady reborn into a typical romance novel happens to spawn as the side character. Suna, who also was a former dweller on earth transmigrated into the same novel as the villainess.
Although there is a great difference between the two...
Sumi's life isn't blooming with the main characters suddenly noticing her, instead she plays into her role just as it was meant for her,
a side character.
Whilst Suna is basking in the attention of her from her former love interest the male lead and her new love interest which was the conveniently handsome villain.
Sumi just watches, while remaining a convenient tool to Suna.
Though she's hopeful to at least have one person that cares about her.