Harald, grief stricken over his love's death, decides to create a tangible expression of his love for Emma. Harald decided to create a virtual daughter, named Aura, who would become the ultimate AI by receiving data on humanity and it's various emotions. To do this, Harald created Morganna Mode Gone, an omniscient AI program designed to collect information and then be Data Drained by Aura, in order to complete her as the Ultimate AI.
In 2006, Harald brings a game called Fragment to the company CC Corp, the vessel for Aura's birth disguised as an MMORPG. However, things do not go as planned. Morganna deletes the maternal part of her program out of fear, and becomes unstable.
Aura, meanwhile, has been sleeping, waiting for Morganna to wake her up. For 2 years Morganna does not awaken Aura. Realizing that things aren't going as planned, Harald leaves his physical body behind to talk to Morganna. Here is a quote by Harald right before his transformation:
AI Harald in .hack//Sign"I must...speak with Morganna.
To go where she is, the living flesh poses a hindrance.
But I must. I must go. For our Aura.
Emma, please give me a little more courage."
Despite his efforts, Harald becomes trapped in the game world by Morganna and restricted to various niches in The World. It is there he stays, trapped in a looped dialogue expressing his regrets and the error he made in creating Morganna. It is this form that BT, Bear, Tsukasa and the rest of the .hack//Sign party find, (dubbed by them as "The Broken Man.") However, he is unintelligelible, repeating the same dialogue over and over again. Tsukasa recognizes "The Girl" he is talking about is Aura, but is data drained by Morganna before he can tell the rest of the party. Later, the party finds a more functioning version of Harald, where he warns the party about Morganna and begs the players to protect Aura, saying "I will gladly receive any punishment...but Aura does not deserve this." Morganna, enraged by Harald's meddling, deletes him, which is seemingly the last of the genius programmer.
However, Harald is not dead. In .hack//Quarantine, Kite and BlackRose of the .hackers meet Harald, although now he is a giant tablet of stone. He is, again, largely unintelligible, but he does impart one phrase that strikes Kite: "It is darkest...before...the Dawn." Kite thinks this means that Harald meant for Aura to become complete, not for Morganna to win and for the coma victims to be lost. Harald is then destroyed by Cubia. Whether this is the last of Harald in The World is unclear; his resilience thus far hints at another possible return. An AI found by Taihaku and Haseo in the Painful Forest event could possibly be Harald somehow still alive within The World R:2, though the area he was in was deleted shortly after Haseo met him.