I leased an artist live work loft in 1997, land lord permitted a roommate, who was NOT required to sign lease

Riki
Just Looking
La Colonia

now I need the space he is taking to work in and he has become an abusive slob who does not need work space, works elsewhere, he started paying his half rent directly to owner's agent instead of me I couldn't stop him or them from accepting and now, some years later that I no longer want roommate, roommate thinks he is equal to me and can overtake my lease hold, can the law force me to live with this abusive pig ? How do I evict him ? I can not find any Law in Los Angeles or California that gives him ANY rights equal or above me or allows him to LIVE IN MY HOME just because the land lord accepts his half of the rent check, He did NOT want the responsibility of co tenancy, did not sign the lease BUT now thinks he has the same rights as me, wants me out, I don't think legally this is correct that he can "invade my home this way, my lease is valid, I'm the only name on it. HELP