Oedipuss

Oedipuss is Mother's pet cat, who is the model for the concrete cat mount that she creates during the fight Robin has with her. The cat normally lives in the Bastion, but as of the civil war that has broken out between the Bastion Soldiers and the One Concern Infantry, Mina has taken them with her from City One.

Oedipuss is left in the house of Robin at the end of the game, and is seen sleeping next to her bed at the final cutscene. Presumably, Robin now owns the cat.