In Hiranyakashipu’s lineage were two demon brothers named Sund and Upsund. They were like reflections of each other and were inseparable.
Both brothers performed severe penance to get a boon of immortality from Brahmadev, however when Brahmadev refused to award immortality they asked for a boon that they should be killed by each other only, knowing they will never turn on each other.
Now to get rid of these two all the gods approached Brahmadev, who requested Bhagwaan Vishwakarma to create the most beautiful woman in the world.
Vishwakarma thus instructed by Brahmadev created Tilottama and Brahmadev instructed her to create feud between two brothers.
When Sund and Upsund saw Tilottama, they started fighting for her and killed each other in the process.
Narad muni narrated this story to Pandav brothers after their marriage with Draupadi so that they never fight among themselves for her.