Draken-Korin gathered the Valheru for the sake of battling the gods as a single powerful entity, and he created the mysterious artifact known as the Lifestone, presumed to be a powerful weapon. The Valheru then united into a single entity which would become known only as "The Enemy". But Ashen-Shugar was the only Valheru who refused to join his kin, believing the battle against the gods to be fruitless. He was beginning to be under the incomprehensible influence of Tomas, which seemed to provide him with the conscience that his kin lacked. At the end of the Chaos Wars, the gods were victorious and all Valheru destroyed except Ashen-Shugar and a badly wounded Draken-Korin. Ashen-Shugar killed Draken-Korin's material form, preventing him from ever activating the Lifestone. He afterward traveled throughout Midkemia, naming all a free people.
An event of note is his speech to the elves. He told them that new beings (the humans and dwarves) had found refuge in Midkemia. The future eledhel were ones to say that they would live in peace with these new beings, while the predecessors of the moredhel were to say that they would war on the humans and dwarves, as they were the ones to "inherit the mantles of power." Ignoring Ashen-Shugar's warning against the gain of power and traveled to the north to dream dreams of power. The ones rendered mad by the destruction in the Chaos Wars snuck off to plot against their brothers, and so they were called the glameredhel. He then traveled back to his home in the Eagle's Reaches to spend the rest of his life, dying thousands of years later. He held a conversation with the essence of Tomas, and then let his essence bleed out of him and into his armor, which would lie in wait for its new host for many more millenia.
Duke Borric's fears of invasion were realized, and the Empire of Tsurannuani attacked the Kingdom through a rift in space-time, controlled by powerful Tsurani magicians, or Great Ones. The Tsurani homeworld, Kelewan, lacked metals that were abundant in Midkemia, thus much of the Tsurani assault was directed at the dwarves of Stone Mountain and of the Grey Towers. Tomas came into his own as a powerful warrior, seemingly possessed when in battle and was admired by the dwarves for his heroics. It was during this time that he started having strange dreams, in which he met Ashen-Shugar and talked with him. He seemed subtly changed each time, appearing to be less the human and more the Valheru that Ashen-Shugar was.
When brought into Elvandar, the city of the elves, instead of being scared (which is how all other humans reacted to the magics of the elves), he instead felt at home there. He grew close to Aglaranna, the Elf Queen. They grew to be lovers, and he continued his subtle change into the Valheru. Tathar and the elven Spellweavers were wary of Tomas, because he was becoming one of the Valheru, who had enslaved the elves in ancient times. Over time, Tomas lost more and more of his conscience, slowly transforming into the long-dead entity of rage and battle-madness. The transformation culminated when the Tsurani prisoners of war were brought to the elven court. He killed several of the helpless Tsurani, commanding the nearby elves not to interfere. He would have killed Martin Longbow, but he suddenly recognized his boyhood friend and warned him not to oppose him. As he continued slaying more Tsurani, he came across a small boy who put him in mind of his childhood friend Pug. This then caused an internal battle, with Ashen-Shugar who wanted to kill all invaders of Elvandar, and Tomas wanting to spare the boy. Tomas won the struggle, by virtue of his memory of his foster brother Pug, and was immediately overcome by remorse for all his cruel acts. Seeking to redress his callousness toward Aglaranna, and quell contention for the throne, he became Prince Consort to the Elf Queen, gaining the approval and acceptance of the elves.
In A Darkness at Sethanon, the Valheru host threatened to return to Midkemia, but was trapped in the Lifestone of their own creation, when Tomas inadvertently activated it when stabbing his sword through a reborn Valheru and into the Lifestone. In the aftermath of the Valheru's banishment, he felt a great portion of his Valheru legacy absorbed into the Lifestone as well, but was reassured by Macros the Black that he would live a long life beside his Queen.
Through the following years, Tomas is content to live in Elvandar, though his son with Aglaranna, Calis, preferred a more active role in service to the Kingdom of the Isles. Eventually, during the Serpentwar, he and the elven hosts of Elvandar aided the armies of the Kingdom, and once again, found himself battling great evils at the side of his childhood friend, Pug. Near the end of the battle, he fought the self-styled Demon King of Midkemia when the latter sought to claim the Lifestone.
More recently, Pug brought a Talnoy to Elvandar, seeking Tomas's memories of his Valheru heritage to find out more about the alien artifact. Shortly after, Elvandar was invaded by evil forces, killing many elves and setting the forest on fire before being driven back. The attack prompted Tomas to leave Elvandar to aid Pug in confronting the evil that sought to claim the Talnoy. Later, while guarding a cavern filled with Talnoys, he fought a would-be raider, Ralan Bek, whose unexpected superhuman prowess surprised the human-turned-Valheru who, noting that the youth only grew stronger with every blow, ended the battle prematurely, something he had never found need to do before.