It is his duty to guard the Red Grail, the holy cup which was used to preserve the blood of Sanguinius after he was slain. It is from this cup that the assembled Sanguinary Priests drink as part of the ritual of initiating a new Sanguinary Priest priest.
Corbulo resembles the Primarch of the Blood Angels, Sanguinius both physically and spiritually. He has become determined to cure the Blood Angels and their successors of the Red Thirst, a quest that has taken him across the galaxy in search of wonders from the Dark Age of Technology. In addition, he shares Sanginius's foresight and has limited abilities in Divination. However while this gift is sometimes used to the Chapter's advantage in battle, he is most focused on researching a cure to his chapter's affliction.
Nonetheless, his skills have been put to good use by the Chapter in other fields. The reason the Blood Angels arrived so quickly to counter the Second War for Armageddon by the Ork Ghazghkull was due to his divination.
However these successes have not come without cost, for Corbulo has become more withdrawn, with some suspecting that he has foreseen a grave future for the Blood Angels.
Armed with a standard issue Bolt pistol and a relic Chainsword named Heaven's Teeth, Corbulo also carries an Exsanguinator and the Red Grail, which not only inspires other Blood Angels to greater acts of valour but also generates a powerful force field.