I Was Reincarnated as the Heroine on the Verge of a Bad Ending, and I'm Determined to Fall in Love! manga volume 6 features story by Kotoko and art by Ikuto Nanase.

Reine and Julius set off for their summer retreat to the Waynewright estate, only to be greeted by the dreaded cousin Cecil! Reine reluctantly agrees to be tutored by Cecil in order to learn more about his academy classmate, a strange girl who calls herself a "heroine"... Is it possible that someone else was reborn in the same crappy dating sim as Reine?!

After spending the week apart from Reine, Julius's jealous streak intensifies upon their return home when Reine goes to visit Yoshida's family home. There, Reine is introduced to none other than Yoshida's big sister, who challenges our determined heroine to a test of love...!