Marcus Valerius was a Praefactor of the Imperial Army during the Great Crusade and Horus Heresy.

馬庫斯 瓦萊里烏斯是大遠征和大叛亂時期的一位帝國軍軍官。

Commanding the Therion Cohort, shortly before the Drop Site Massacre Marcus' forces were stationed on the Raven Guard homeworld of Deliverance. During his stay on Deliverance Marcus began to become haunted by strange dreams that seemed to foretell catastrophe for the Raven Guard. Raven Guard commander Branne became suspicious that this was an omen, and eventually left for Isstvan V to see if their Primarch Corax was okay. When they arrived in-system, the Raven Guard had been massacred and Branne was able to save Corax himself.

馬庫斯是瑟瑞昂步兵隊的指揮官，登錄點大屠殺前不久他的部隊駐防到了暗鴉守衛(wèi)的母星：拯救星。在他駐扎在拯救星期間，他開始經(jīng)常被怪異的夢境所纏繞：內(nèi)容似乎是關于暗鴉守衛(wèi)軍團的災難預見。暗鴉守衛(wèi)的指揮官巴蘭（機仆：看家的鴉衛(wèi)連長，首屈一指的空降大師）懷疑這是一個征兆，并最終動身前往伊斯特萬星系查看原體克拉克斯是否一切安好。當他們到達之后，（發(fā)現(xiàn)）暗鴉守衛(wèi)已經(jīng)慘遭屠殺，巴蘭救回了克拉克斯本人。

Later, Marcus led the Theroion cohort in the attack on the Perfect Fortress.?However after having visions of Leman Russ meeting his end at the hands of traitor forces, Valerius confided to Corax of the supernatural nature of his visions as well as his belief that it was the guidance of the Emperor, who he now worshiped as a god. This enraged Corax, but he nonetheless followed Valerius' visions, resulting in the Raven Guard saving the Space Wolves in the Battle of Yarant.

后來，馬庫斯率領瑟瑞昂步兵隊參加對于完美要塞的進攻。不過在看到黎曼 魯斯將死于叛徒部隊之手的幻象后，馬庫斯向克拉克斯吐露了自己幻象的超自然本質(zhì)以及他的信念：這是帝皇的指引，現(xiàn)在他將帝皇作為神明進行祈禱。這激怒了克拉克斯，但原體仍然跟隨了馬庫斯的幻象，結果就是暗鴉守衛(wèi)在雅蘭特戰(zhàn)役中拯救了太空野狼軍團。

Due to his beliefs, Corax banished Valerius and his sight. He eventually made his way to Beta-Garmon, where he led the Therion Cohort against enemy Titan's in the Battle of Beta-Garmon.

由于馬庫斯的信念，克拉克斯放逐了馬庫斯，不讓他在自己身邊使用預知能力（機仆：鴉王比較反感靈能）。但馬庫斯最終前往了貝塔 伽爾蒙星系，并在那里率領瑟瑞昂步兵隊與叛徒泰坦軍團交戰(zhàn)。