Father Renaldo is Archbishop Enrico Maxwell's right-hand man, and the second-in-command of the Iscariot Organization.
He was the one who had informed Paladin Alexander Anderson of a vampire attack in Badrick, Northern Ireland, and of the Hellsing Organization's involvement in containing the attack. He is seen later at the London Imperial War Museum escorting Enrico Maxwell, to meet Sir Integra Hellsing, to discuss the issue of Millennium. He is seen for the last time in volume 4, at the conference that Hellsing and Iscariot held with the Queen which quickly turned into a declaration of war meeting at the arrival of Schrödinger. Not much is known about him afterward, though it can be assumed that he did not take place in the Battle of London and became one of the few Iscariot members survivors known by the end of the series. Like all members of Iscariot, Renaldo is fanatically devoted to the Catholic Church and to Iscariot's holy mission. He seems to act (like Walter to Integra) as a 'bodyguard' to Maxwell, and appears to wield a sword, although he only brandished its hilt briefly. He also appears in Volume 8 flashback taking a young Enrico to Anderson. It can be assumed that due to his age he passed away 30 years later.
- A prototype version of Father Renaldo was in a manga series called, Magic School.