The Fateless One is the protagonist in Kingdoms of Amalur: Reckoning, a mortal being who was resurrected in Fomorous Hugues' Well of Souls - the first and last "true" success of the project before the Tuatha Deohn destroyed it. The Fateless One has no memory or recollection of life before the resurrection and soon finds out they possess a power equal to that of gods as the only being capable of changing the fate of events, for better or worse.
The Summer Fae's High King Titarion and the world tree, Nyralim, show some worry about the possibilities that the Fateless One's impact could have upon the future of Amalur, as it is impossible for any Fateweaver to see what impact the Fateless One will have upon any event. Even the Tuatha are moving to hunt down and kill the Fateless One for reasons of their own. Others, like Alyn Shir, who appears to have known the Fateless One before his/her death, see much hope that the Fateless One can bring an end to the war with the Tuatha, however.
The Fateless One once worked as part of a secret organization that's sole mission is to keep the existence of Tirnoch a secret from the world to ensure no one attempts to free her. To get into Bhaile, in order to assassinate Gadflow and reseal Tirnoch, the Fateless One managed to get hired by Templar Octienne to be a personal assistant to Fomorous Hugues' former partner in his Well of Souls project, Ventrinio. Working to assist him in his research, the Fateless One went along and gathered massive amounts of Prismere as a power source for his well. Ventrinio was so impressed by the Fateless One's efforts, he attuned their soul to his Well of Souls. After having gathered enough, he went on with his main mission in secret, only telling Ventrinio that they were going to search for the true source of the Prismere.
The Fateless One failed in their attempt to kill Gadflow and reseal Tirnoch once again, just as the Fateweavers had foretold. But Tirnoch planned to use the Fateless One as the instrument of her revival. Knowing that the Fateless One would return, she made it so that they were resurrected by the Well of Souls created by Hugues.
Before their death, the Fateless One was ruthless, cunning and murderously cold-blooded according to dialogue with individuals who met them pre-mortem. In fact, the Fateless One's personality may have been more vile than that of Tirnoch's. The Fateless One now changes the history of Amalur. Whether it is for a better future or one far worse than the Tuatha planned, is not known.
The Fateless One's personality is determined by the player via dialogue option where they can either be hostile or diplomatic, thus NPCs will react based on their response.
According to Ventrinio, prior to their death, they were hired by Octienne as Ventrinio's assistance for being "very resourceful". Even the gnome professor remarked the Fateless One as an excellent assistant. However, they were not a very good person, as they were described as unpleasant and a terror to be around. They met their end in Alabastra in an effort to bring more Prismere for Ventrinio's Well of Souls, despite his objection, with the help of Callis Dren of House of Pride.
Since the Fateless One does not have any dialogue lines, below are some quotes of various personae around Amalur describing the Fateless One.