Piotr Grigorovich Andreyev was a Ukrainian-Born enlisted UNSC Marine and later, a UNSC Ranger. Andreyev continued active service throughout the Remnant and Necros War eras, and was eventually awarded a Colonial Cross for his actions during the War. He would later retire from the UNSC Marine Corps as a commissioned Officer, and would go on to write two memoirs on his life and military service before his death.