Tawnos was a Jorilinian toymaker who came to the city of Kroog to be an apprentice for the great artificer Urza. He impressed Urza with his clever designs based on animals.

Tawnos became known as Urza's greatest assistant. Upon the creation of clay statues, which had the ability to regenerate, which proved very useful during the catatrophic Brothers' War, he was promoted to the rank of master artificer.

At the conclusion of the war, Tawnos was placed in a coffin of his own creation which was used to keep a person in stasis. After five years in stasis, the now-planeswalker Urza returned and told Tawnos to tell his wife, Kayla bin-Kroog that he had died. Tawnos returned and told Kayla what Urza had said, but she didn't believe him. Tawnos helped Kayla raise Urza's son, Harbin, in the shattered continent of Terisiare.

Note: Tawnos's most notable inventions were his clay statues, coffin, amazing weaponry, and Urza's personal armor.