I get that OC can mean lots of things, but I think most people in this thread are willfully misunderstanding you because of preconceived biases about original characters being 'childish.'

I will instead attempt to engage in good faith. Here is an original character I conceived for a Star Control D&D game I ran. Archivist Ryll (pictured at right) is an Yllk who joined the crew after they performed a mission to help him study an anomalous neutron star. He is pragmatic and cheerful, and always game to help out, but dislikes authority figures. He lost his rear legs in an accident involving IDF (interdimensional fatigue). He is shown here in the epilogue of the campaign in his capacity as archivist, assisting with the official documents as the Alliance of Free Stars signs a formal cease-fire with the VUX Admiralty after the Battle of the Sa-Matra and subsequent dissolution of the Ur-Quan Hierarchy of Battle Thralls.