Tree of Inifuss

From Diablo Wiki

The Tree of Inifuss is an ancient tree standing in the middle of the Dark Wood. It holds many mystical properties, such as the key to unlock the magical Cairn Stones. The Tree of Inifuss is guarded by Treehead Woodfist and his minions, a fierce Brute that does anything to prevent players from reaching the sacred Tree.

Reaching the Tree is needed for The Search for Cain quest. Players need to obtain the Scroll of Inifuss, the rune-inscribed bark of the Tree of Inifuss. Akara will then proceed to translate the runes so that players can unlock the Cairn Stones.