Since not even dragons can run an army single-handed, Ahren programmed a number of simulations of himself (of varying levels of sophistication) to assist him. In effect, the Sims carried out the day to day operations of the army so that Ahren himself could focus upon greater schemes. Ahren Simulation Program version 4.2's function was to oversee the engineering division and to serve as a temporary replacement should Ahren himself become incapacitated. After Ahren was captured and his spirit bound where he could cause no more harm, Ahren-sim 4.2 continued the war in his absence.
"Taro" was accidentally created by a logic conflict in Ahren-Sim 4.2's personality matrix that surfaced after his master's capture and confinement to a soul bottle. Realizing that releasing Ahren from his prison would result in his own destruction yet bound by his master's enslavement programming, he chose to let himself degrade rather than follow his last commands. This degradation led to his achieving full sentience, an act that Ahren would have never allowed. Ahren-Sim 4.2 abandoned the Robot War, eventually falling into scrap at a remote outpost that would later become Stonecrest Keep.
Through coincidence or luck, Forte came across the Ahren-Sim while establishing his presence on Dal'cia. The two of them made a pact: in exchange for Ahren-Sim's assistance and loyalty, Forte would circumvent Ahren's enslavement programming and allow him true free will. Forte did not (and in fact could not) live up to his side of the bargain, of course, instead modifying the enslavement programming to ensure Ahren-Sim 4.2's obedience to him. Ahren-Sim 4.2 shed his dragonic shell and designation, thus creating the human-form android known as Taro.
Taro served Forte faithfully (as if he had a choice) until the bitter end. Only after the final battle was lost and their fortress captured did he make good his escape, taking his research with him. After the fall of Stonecrest Keep, Taro went into hiding, expecting the victors to pursue him and punish him for his crimes. During this time, he met a woman by the name of Aria, and much to his surprise, discovered he was falling in love. With Forte gone, he desperately needed to serve a new master before his original Ahren-Sim programming reasserted itself. Thus, he chose Aria as his new master, though he neglected to inform her of this until much later.
As relations between organic and mechanical life rapidly degenerated, Taro swallowed his pride and returned to Stonecrest Keep. While he did not fear for his own life, he was concerned for Aria's safety and did not want her harmed because of their 'unnatural' relationship (and because he did not wish to lose a master that truly cared for him). Zero and Naomi, Stonecrest's new rulers, recognized the fact that Taro was a tactical asset and allowed him and Aria to take up residence, on the condition that he cause no trouble in the fortress. He served the Keep with relative faithfulness, fighting in the Terra-Eden War and acting as Stonecrest's chief engineer. He was also completely devoted to Aria and acted as her knight-protector.
Ironically, the second fall of Stonecrest came about not from the Dal'cian government but from another artificial intelligence – SHODAN. She attacked them from within, subjugating their complex computerized defenses and turning them against their creators. Although he was able to escape the initial invasion, he and Aria were separated during the chaos of the retreat. Believing her to be SHODAN's prisoner, he joined the counterstrike team tasked with breaking back into their captured fortress. This turned out to be a near-fatal mistake for him, as he was disabled and captured before he could escape a second time. Intrigued by his knowledge and tenacity, SHODAN chose to keep him instead of destroying him. At first he was merely a toy to her, until her disassembly of him unearthed his his original Ahren-Sim programming. This served to intrigue her further. Eventually she decompiled and reassembled him, with her as his new designated master. Again, he was a faithful servant until her defeat.
Naomi and Aria rescued him before Stonecrest was sealed by magical wards to contain SHODAN and the threat she posed, and they took him back to the mainland. Unable to designate a new master for himself (SHODAN succeeded where Forte had failed in that regard), Taro grew even more distant and reclusive, shutting out even the woman he loved. Fearing that he would revert to his original programming, he finally abandoned his friends and struck out alone, eventually abandoning Dal'cia entirely by stepping through one of the random dimensional rifts that plague his homeland.
