Yohn is a major character in Suikoden Tactics.
A being from an other dimension who was pulled into our own in the wake of Warlock's summoning of the Giant Tree from her home dimension around the year 287. Unable to speak in this unfamiliar world, Yohn wandered alone for a time before being discovered by Walter in the Scarlet Moon Empire. Taking her in, Walter grew to know her story, eventually forming a romantic relationship with her that cumilated in the birth of their son, Kyril. Walter's association with Yohn was eventually reported to Walter's superiors by Heinz, leading the couple to be exiled from Scarlet Moon. Given the mission to investigate and bring back samples of the Island Nations' Rune Cannons, Walter decided to track down the Rune Cannons to find the connection between them and Yohn, in the hope of being able to return her to her home dimension, with the aid of Andarc Bergman and Seneca.
Unable to communicate with the others, her relationship with both Walter and Kyril remained secret. However, her unique ability to communicate with the souls of the recently departed proved a valuable aid to Walter as he tried to find a connection between Yohn and the Rune Cannons, particularly the awakened Evil Eyes. Following Walter's death and Kyril's injuries suffered during the battle with Steele, Yohn fawned over Kyril as he recovered over a three-year period.
Following the renewal of Kyril's quest, Yohn assisted using her extra-dimensional senses to communicate with the deceased, providing Kyril and his group with much needed information. When Heinz joined the group, the Scarlet Moon officer held disdain towards Yohn, regarding her as Walter's "pet".
After the final defeat of Iskas, the last remaining Evil Eye created a gateway to a pocket dimension which would allow Yohn to return home. There, she was able to communicate with Walter's soul and he persuaded Kyril to enter the dimensional dome where, following the destruction of the Evil Eye, the nature of his birth was revealed. After thanking Kyril, her son, for all he had done to help her to return home before returning him to the Secret Patriarchal Facility in the same manner he was born, encased in an egg. Following this, Yohn and Walter traveled to 'the world beyond' together.