Tanis was born in Qualinost in the year AC 258. He was the son of Elansa Kanan, sister to the Solostaran Kanan, the Speaker of the Sun. Less than a year before Tanis's birth, Elansa and her husband Kethrenan (Solostaran's younger brother) were ambushed by a band of humans. Kethrenan was slain and Elansa was raped and left for dead. Elansa lived miserably until she died after giving birth to Tanis. The name "Tanthalas" (which means "ever strong" in Elven) was given to him by Elansa's midwife, Eld Ailea.

Tanis was taken in by Solostaran to be his ward. Being a half breed in an elven community, Tanis was the constant target of ridicule. The only one who seemed to accept him was Laurana, Solostaran's daughter. Since they were children, she vowed they would marry someday. His feelings for her were mixed, which he blamed on his mixed heritage. When Tanis was a boy, he befriended Flint Fireforge when Flint was invited by Solostaran to stay in Qualinosti to serve as a craftsman for his people. Tanis and Flint left Qualinesti many years later and settled in Solace.

Some years later, Tanis met Caramon, Raistlin, Sturm, and Tasslehoff in Solace. While venturing back from visiting Qualinesti one day, he came across Kitiara fighting a pack of hobgoblins. From that day on, the two had a love/hate relationship. Tanis and his friends shared many adventures, each bringing them close to death and closer together. He and his friends parted ways and promised to meet again after 5 years.

Upon his return, he and his friends were thrust into the roles of heroes when evidence of the true gods was revealed. Tanis went on to become a leader, not only of his friends/companions, but of the War of the Lance. It was he who inevitably defeated the Dragon Highlord Ariakas (with help from Raistlin) and put an end to the War of the Lance. During the war, he was torn between his love for Laurana and Kitiara. Soon after the war, though, his true feelings for Laurana emerged and they were married.

Tanis was honored by humans, elves, and dwarves alike, receiving their highest honors and respect. Tanis and Laurana traveled across Krynn serving as political advisors and helping those who suffered the wounds of war. They eventually settled in Solanthus. Tanis has one son, Gilthas, named after Laurana's brother Gilthanas.