A limited express train that inherited genes from the 0 series. A 2-car set, primarily operating as the Tsubaki and Asakaze limited expresses. A boy who is always energetic. His favorite food is beef bowls from Yasukoya.

A limited express train introduced to replace the 119-6000 series. Primarily operates as the Yamakaze limited express. A quiet girl who wears glasses. Her favorite food is shortcake.

The younger sister of the 2500 series. A dedicated train for group tours with various luxurious facilities. The other trains of Obakyu Electric Railway call her Fu-chan, except for the 2500 series. Her favorite food is ice cream.

The diesel multiple unit (DMU) version of the OB778 series. Primarily runs on the Hikane Line as the Hoshimi limited express. He is friends with the BEC2000 series. A boy who is said to be quite handsome. His favorite drink is Ramune.

The Tsubaki-colored version of the OB778 series. Primarily runs in 3-car sets. She mostly operates as the Tsubaki limited express (sometimes coupling to form 6-car sets). A brave girl. Her favorite food is pickled plums.

The multi-purpose version of the OB778 series. A 3-car set. Operates in various roles such as the Tsubaki and Yamakaze limited expresses (also sometimes coupling to form 6-car sets). A boy who is reportedly quite mischievous. His favorite food is Yakiniku.

The elder sister. A train designed for the Obakyu Trans-Express. Also a 3-car set. Often operates in 6-car sets coupled with the Tsubaki or Multi-Purpose versions. She is tall. Her favorite food is macarons.

The younger sister. A train featuring the renewed livery of the Obakyu Trans-Express color. Also a 3-car set that sometimes couples into 6-car sets. She is also tall, though 5cm shorter than the Trans-Express Color. She gets along well with her sister. Her favorite drink is bubble milk tea.

The general-purpose 4-car version of the OB778 series. A big brother figure. Operates in various services like the Yamakaze and Tsubaki limited expresses. A tall, handsome boy who wears glasses. His favorite food is consommé soup.

A set that appeared exclusively for the 2024 April Fools' event. The younger sister of the KiHa 778. Also a 2-car DMU. The interior is chaotic, featuring long seats and even hand straps. Apparently, there is no restroom. A girl who wears glasses; she has a clumsy personality but is deeply sincere deep down. She usually works as a staff train for Obakyu Electric Railway. Her favorite food is Ochazuke.