Thorn along with the Kings of Pure Color attained level nine and decided to create a treaty that separates their territories and disallowed fighting amongst each other to obtain level ten. She was with the other kings during a meeting where she watched Red Rider get killed by Black Lotus.
Crimson Storm Princess Arc
Purple Thorn only makes an appearance in a flashback that Yellow Radio had previously recorded to incapacitate Black Lotus when he showed it to her. It is revealed during the this flashback that the Kings of Pure Color were having a meeting. Red Rider was expressing his opinion against fighting amongst each other and stated that he had respect with one another. Black Lotus replied that she too had respect for him and decided to hug him as a sign of respect. However, the Purple King, Purple Thorn stated that was too much as a sign of jealousy. However, Red Rider responded by stating that it's Black Lotus' way of shaking hands since she doesn't have any. Black Lotus took advantage of his kindness and used her ability, Death By Embracing to kill him. Purple Thorn started screaming in horror and she and the other Kings attacked Black Lotus. Once the thirty minutes were up, Black Lotus linked out and went into hiding.
She holds one of the Seven Arcs, The Tempest. It is speculated she is an electric user considering her obsession in recruiting other electric users into her legion.
- It is implied during the flashback, that Purple Thorn was romantically involved with the Red King, Red Rider.