Jarsyl was the first-borne child of Harbin and Melana, a member of Kayla's court in Argive, and the product of an arranged marriage by his grandmother, Kayla bin-Kroog. He was just a child living in Penregon at the time of the blast at Argoth in 64 AR, and frightened by the effect, as recorded in "The Antiquities War." His father died in the blast, and he was raised by his grandmother.

After the fall of ancient Argive, his grandmother founded a large manor in what became Giva Province. Jarsyl was black-haired and stocky, charming, amiable, and quick-witted. As an adult, Jarsyl became a very powerful wizard, performing his studies in a tower he built on the edge of the manor. His notes and journals became the early basis for the magical awakening in the period of the Ice Age and beyond.

One of these discoveries involved the theory of the Multiverse, an infinite collection of worlds, or planes. One of these planes he was able to magically open a gate to, a world of acid rain, fetid swamps, and metallic vegetation.

"The warm rain of grease on my face immediately made it clear I had entered Phyrexia." —Jarsyl, Diary

He apparently travelled to Phyrexia, and was never seen in Dominaria again. His notes were then taken by his apprentice and his tower in the swamp fell into disrepair.

Jarsyl was survived by at least one granddaughter, who became the grandmother of the Archmage of the Unseen, Jodah. Jodah's early magical experiments involved attempting to recreate the gate spell of his great-great grandfather, but failed as he used the mana from the current state of the tower (white), rather than the original state of the tower (black).