Ohio Rev. Code § 2123.02: Petition - defendants.

In a situation described in section 2123.01 of the Revised Code, the executor or administrator may file in the probate court of the county where the estate is being administered a complaint signed by the executor or administrator or the executor's or administrator's attorney, which complaint shall be verified. The surviving spouse and the legatees and devisees, or the heirs and distributees of the decedent, including those whose names are unknown, shall be made parties defendant. The complaint shall contain a concise statement of the pertinent facts and shall conclude with a prayer, for the determination of the heirs and distributees of the decedent or of the devisees or legatees not named in the will and their respective interests in the estate.