A great warrior and leader among his people (the brutal and mirthless Tharks), he possesses a sense of compassion and empathy uncharacteristic of his race.

[2] In the first novel, A Princess of Mars, with the help of the newly arrived Earth man John Carter, he becomes Jeddak, or king, of the Tharks.

The attempt fails, and Tarkas instead takes Carter prisoner and transports him back to the nearby dead city, in which a group of Tharks have taken up temporary residence.

Carter also discovers that Tarkas has a secret: long ago he fell in love and had a child (egg) with his lover, Gozava, two actions punishable by death in the Tharks' culture.

Gozava's maternity (although not the child's identity) was discovered, and she was tortured and killed by the Tharkian chieftain Tal Hajus for the crime of childbearing.