|Game||Tales of the Abyss|
|Japanese Voice Actor|| Hencken|
Class I is a trio of researchers in Tales of the Abyss consisting of Hencken (ヘンケン Henken?), Spinoza (スピノザ Supinoza?), and Cathy (キャシー Kyashii?). Settled in Belkend, they are rivals to Sheridan's Class M.
Hencken serves the role of leader for Class I and primarily works with Cathy, as Spinoza betrays the group by working with Van Grants, having been involved with the original Luke fon Fabre's kidnapping seven years prior to the events of the story. Spinoza continues working with Van during the game's plot, leaking information that eventually leads to Hencken and Cathy's deaths. The protagonists collaborate with Hencken and Cathy in modifying the Tartarus to descend into Auldrant's core and stabilize its vibration in hopes of reducing the production of miasma. In protecting the group, Hencken and Cathy are killed by Van at Port Sheridan, and Spinoza thereafter assumes responsibility for their deaths and agrees to atone for his actions by working with the group.