Giddianhi was the governor of the Gadianton robbers, a secret society, who about AD 16 sent an epistle to Lachoneus, chief judge of the Nephites. In it he praised the firmness of Lachoneus and his people, then demanded that they yield up their cities, lands, and possessions and unite with the robbers, threatening to send his armies to destroy them if they refused. He claimed the society was of ancient date and that the robbers were recovering rights of government taken from those who had dissented to them, and signed the letter in his own name (3 Nephi 3:2-10).
The Nephites gathered under Lachoneus and their chief captain Gidgiddoni, fortified themselves, and prepared for the robbers’ assault rather than attack them in the wilderness (3 Nephi 3; 4:1). Giddianhi’s armies came against them in AD 19 because they could not sustain themselves except by plunder. When they rushed the Nephites, who fought in the strength of the Lord, the battle and slaughter were great, and the Nephites beat the robbers and drove them back (3 Nephi 4:10–11). Giddianhi, who had fought with boldness, was pursued as he fled, and being weary from much fighting was overtaken and slain (3 Nephi 4:14).