Conan the Barbarian’s life was saved by a symbiote a few issues back. It died during the Savage Avenger’s battle against Kulan Gath, and now during the events of King in Black, it somehow was brought back to life and sought out Conan again. The symbiote narrated its long history of being tortured and abused by Kulan Gath, and seeks revenge. It offered to partner itself to Conan as a tool of vengeance against the mad wizard.
Pretty good solution by Marvel to give Conan some sort of plot armor. This way he can participate in really dangerous storylines without having to explain how he could survive them as a human.
From – Savage Avengers #18