Lancer's True Name is Hagen von Tronje, most known as the trusted vassal of King Gunther of Worms, and the treacherous villain who kills the famed dragon-slayer Siegfried in a cowardly sneak attack.
Hagen was born from a scandalous affair between Queen Uote of Worms and King Alberich of Nibelungs. A bastard, his lineage was just acknowledged when King Etzel of the Huns demanded hostages from his allies, yet the eldest prince of Worms, Gunther, was only an infant. Hence, he was sent to Etzel's care in place of the too-young child, and under that savage king, learned the art of war.
Once Gunther takes the throne in place of his dead father, the young king refused to pay the Huns any longer, and the older yet still young knight ran back to answer his king.
A talented fighter, in the style of Hunnic savages, Hagen rose the ranks until he became known as King Gunther's most trusted advisor and strongest warrior. Once Siegfried arrived in Worms to win the hand of the most beautiful Kriemhild, it was he who advised the king to allow the man to stay and help them through troubles-winning important victories and even the hand of Queen Brunhild of Iceland, which Gunther so wanted.Before long, that truth of the trick was revealed, and Brunhild's pride, a queen's pride, broken. Hagen then faced demands for Siegfried's death, not just by the wounded queen and her husband, wanting to appease her, but even from the hero himself.
Unable to talk a way out of this situation, though he had shared cups of brotherhood and called Siegfried a friend, he searched for that man's weak point, found it, and formed a plan, knowing the whole time he was to carry out a cowardly act. Trusting only his blade, he plunged the spear onto a leaf-shaped mark, into the back of a man bent over to drink. The hero accepted the spear going through his back without a fight.
Soon after stealing Siegfried's possessions and sinking Das Rheingold into the river it's named after, Hagen saw a predicted tragedy unfold before his eyes, as the newly widowed Kriemhild cried for revenge. The story made to cover up that death is too flimsy against solid evidence - the possession of Balmung, the wound bleeding fresh once Hagen walked near the corpse. Thus, Kriemhilds hatred burned not only for the killer, but also to his accomplices.
Soon, the widow remarried to King Etzel and came up with a plan for revenge, inviting the Burgundian royalty to a party in the court she now loves more than ever. Before setting off, the ever-wise Hagen forced a prophecy from a group of water fairies, and was told that no one but the chamberlain will come back alive. After the chamberlain swam back to shore after being tossed from the boat, he advised the craft to be destroyed - no one will come back alive anyways.
Of course, the prophecy came true, and soon Etzel's court was filled by fire, Hunnic and Burgundian corpses alike, as well as the heads of Hagen, Gunther, and Kriemhild who was soon fell for her crimes.