Commanding Clan Raukaan as of 997.M41, he was defeated in battle by the Necron Overlord Akanabeth. Afterwards, Akanabeth offered the captured Grolvoch a choice - swear fealty to the Overlord or be killed by his hand.
Grolvoch's fate at the hands of the Necrons is unknown, for he was still leading Clan Raaukan after the formation of the Great Rift. Burning with a desire for vengeance, he launched a reckless assault on Sabbyst against the Daemon Primarch Fulgrim. Grolvoch was killed standing before the Primarch in order to allow for refugees to escape.