| Spoiler Alert: This page contains minor spoilers from the events of the games. |
Don't worry too much about them but take it into account.
The Guma siblings were a team of martial artists greatly renown for their talent, as both were very skilled and got some level of fame for it. The elder brother, Nirot Guma, had won the Martial Arts National Tournament in the year LP0005, while the younger sister, Reave Guma, won the one from LP0006 where her brother got fourth place.
At some point, the two siblings left on a journey along with their manager to train themselves on Rising Dragon Mountain, but they did not come back. A petition was made to the Keith Guild to find them, which was accepted by Rance and his party. They came across the Guma's manager, who was in a dejected and despondent state, cursing himself and the world. Crook Mofus determined that his Soul had reached 85% contamination, and that he had to be killed before he reached the critical point where his soul cannot be cleansed anymore, so Rance beheaded him on the spot.
Soon after, the party managed to find the dreadful scenery of the Guma Brothers where Nirot, the elder brother, was sexually harassing his sister. Having lost the tournament this year has led him to develop intense feelings of discontent and grudge towards his sister, and upon being exposed to Soul Shackles, he lost his sanity and started abusing his sister. Crook quickly concluded that he already reached 100% contamination and that his Soul was forever lost, straying away from the Reincarnation Cycle. Due to this, Nirot was sealed and the younger sister, whose Soul contamination was still relatively low, was rescued and taken back to the Free Cities Alliance.