Graham and his son got caught up in the nobles' attack on the small village on the border with Kooluk. The boy, who at that time bore the Rune of Punishment, used it to decimate the attacking nobles, along with the village itself.
Using the rune understandably killed the boy, and the rune transferred to Graham, who now found himself with the blame for the massacre, and fled the Scarlet Moon Empire into Kooluk.
Cray feverishly searched for a way to escape the curse of the rune, having seen what it did to his son. Finding nothing, he simply cut off his left arm to remove the rune from his body. This worked, but he would eventually regret this, and lusted after the power that he once had. Graham took it upon himself to search for the rune, wherever he had to look, and whatever he had to do to whoever had it.
Forming the Cray Trading Company, Graham sold weapons (including Rune Cannons), along with other goods. Graham's ships were a strong presence on the seas of the Island Nations and the Kooluk Empire, dealing with both nations, specializing. However, secretly, he was gaining sway over the Kooluk government, especially the Governor of El-Eal, and worked with them to expand Kooluk's borders southward into the Island Nations. Cray's trusted spies, such as Ramada, would act as merchants, and deal with the Island Nations, just to gather intelligence.
Hoping that war between the two countries would smoke out the bearer of the Rune of Punishment, Cray kept mercenaries in his employ to help him search for and retrieve the Rune, including Kate, Akaghi, and Mizuki, the latter two reporting to Ramada. When he found Lazlo, he sent Ramada, Akaghi, and Mizuki to Obel to assassinate him, hoping for one of them to bear the Rune after performing the task. He would then be able to kill them and bear the Rune itself.
All Graham's plots for getting the Rune failed, and eventually the Island Nations, under the tactics of his old boss, Elenor Silverberg, fought back successfully, forcing him to a final standoff at Fort El-Eal. Here he finally encountered Lazlo, and awakened the Giant Tree to fight him.
The Giant Tree was defeated, and Graham now found himself in the crumbling ruins, with no chance of getting the Rune. Miraculously, he survived the initial collapse, and was approached by Elenor. Knowing that she wished to ask about his reasons, he refused, knowing that leaving her in the dark about what happened since they worked together would hurt her most.
The fortress continued to collapse with greater power than before, and Cray's survival of this ordeal is unknown. However, given the magnitude of the second collapse/explosion, and his disappearance from all recorded history after that point, it seems unlikely.