Alcuin
From Warhammer 40k - Lexicanum
Alcuin is a Justicar of the Grey Knights. Answering the pleas of help from Trajann Valoris, he and his squad would be deployed on Terra during the Noctis Aeterna in order to help Shield-Captain Valerian in suppressing the growing chaos cults. Unfortunately, they would be too late, as the cults had succeeded in summoning an immense Khornate Daemon army from the Warp.[1a]
During the Sack of the Lion's Gate Alcuin fought against a Bloodthirster alongside Valerian, his battle-brothers and the Sisters of Silence. After Valerian stabbed the daemon's throat, Alcuin smashed its ribs with his Daemonhammer while the rest of the team tore down the body.[1b]