MagnaBad
Eris (a princess that physically looks like Princess Iris) was created by Gramorr from Timeline "M" using Iris DNA from the said timeline and magical abilities but redeemed herself by joining the group as an ally and also known as "Princess of Ephiris" (Ephiris is a new planet replacing Ephedia in Timeline M after Ephedia was destroyed by Gramorr using an artifact) , Unlike the Ephidian princesses, Eris casts Diamond magic (something unique about Ephiris)
Short Story: In the timeline "M," Gramorr, the evil wizard, kidnapped Princess Iris and sampled her DNA and magic to create Eris, hopefully to help him take over Ephedia However during a confrontation with the Quintet (From the "M" timeline) Iris persuaded her in a dire situation that if she's truly like her, she should easily overcome her dark side which prompted Eris to get rid of her dark side and fight alongside the Quintet.
During the final fight against Gramorr in Ephedia which the girls had the upper hand against the villain, Gramorr used a banned forbidden Ephedian artifact (Known as the Stone of Apocalia) that Eris stole a while ago and unleashed it , making the whole planet explode. However, Eris managed to escape the awful apocalyptic explosion. By using an artifact, she also stole called the "Vanderstock" Medallion, which can make the user travel in another timeline or dimensions.
Eris ended up in the "K" timeline of LoliRock , whose life truly begins among the Quintet of that timeline.