Altan Trengsin is one of the last surviving Speerly since the Speerly Massacre and the Commander of the Cike.

Altan Trengsin is one of two known survivors of the Speerly Massacre during the second Poppy war. He was trapped in a cell as a subject of experiments by the Mugenese for years. After he was rescued he was taken in by Master Irjah, who trained him as a warrior and helped feed the opium addiction the Mugenese had started. By the start of the book he is in his final year at Sinegard Academy and the star of the school.

Altan was a student at Sinegard Academy for five years. During that time, he became the combat and academic star of the school. During his first year, he had an intense rivalry with Tobi, which concluded with the final fight of their combat trials in which Altan was victorious.

In his first year, Masters Jiang and Irjah fought to have him as a student for Lore and Strategy, respectively, but the Empress stepped in after watching the combat trials and forced Altan to pledge Strategy.

After the Academy, Altan is sent to join the Cike due to his power. A few years later, Commander Tyr is killed, and Altan takes over as Commander of the Cike. As commander, he is shown to be stern yet caring and protective towards to the members of the Cike, being especially gentle with Suni and defending Ramsa from the other warlords.