Treyni/Chronology

Forest Disturbance Arc
She met one of Souei's clones during his investigation of the orc army and insisted that she meets Rimuru. She made her appearance in a meeting, where she confirmed the presence of an Orc Lord and asked Rimuru to defeat it.

Sometime later, she confronted Laplace and Gelmud and levied "divine justice" against them. She cut off one of Laplace's arms, but they escaped before she could finish them off, leaving her dissatisfied.

After the battle between Rimuru and the Orc Disaster, a conference was held to determine the fate of the orcs. Treyni attended the conference as a representative of the Treants. The Jura Forest Alliance was soon established, and she appointed Rimuru as their leader. Treyni and the Treants offered to provide a food supply for the orcs.

Demon Lord Attack Arc
She appeared with her sisters to witness the duel between Rimuru and Gazel Dwargo.

She later appeared during the battle against Charybdis and aided Rimuru's troops and the Pegasus Knights. After the battle, she questioned how Phobio discovered the location where Charybdis was sealed. The interrogation revealed the Moderate Harlequin Alliance as one of the factors responsible for the Orc Disaster and Charybdis incidents.

She was seen again answering some questions from Rimuru about Superior Spirits.

Human-Monster Interaction Arc
She appeared briefly to inform Rimuru about the arrival of the Eurazania's delegation and Youm and his group.