Angus Weir was an early 19th century warlock who sold his soul, but then sought to cheat his masters in Hell. In 1813, on All Hallows' Eve, the lords of Hell sent a horde of demons to snatch up Weir and his house from off the coast of Scotland, and brought it to Acheron. Weir did not survived the trip, but with his dying breath he renounced all his evil works and begged that he be forgiven and inscribed magical wards which barred any demon and creature of Hell from ever entering his home.
Weir's home was later visited by Sir Edward Grey when he was brought to Hell guided to the warlock's home by some unknown creatures. There Angus acted as Grey's teacher in the magical arts.
Somehow Grey escaped Hell to wander the earth. When he returned to Hell, Edward brought Hellboy to Angus's home as a safe haven. After Hellboy departed, Angus Weir's spirit conversed with Sir Edward and chastised him for making Hellboy believe he is free when he is destined to do more horrible things.
After Ragna Rok Weir witness Edward Grey defeat Eligos after the former occultist fully embraced the power of Acheron becoming a personification of it. When the other personfications of Hell's river came and invited Grey into their ranks, which would require him to forgot his humanity, Weir urged his student and friend to accept the invitation as Grey would become something else than he was. If he did not then Grey would be condemned to be the last demon of Hell.[1]