The Tree is the link to heaven in the Underworld. Most bats in the Underworld do not know of the Tree due to the fact that they are unintentionally misled by Cama Zotz. Shade, Yorick, Java, Murk and Nemo traveled to The Tree during the events of Firewing. The Tree is not only heaven to dead souls, which truns them into just a consiousness, unable to interact with other beings, but more of just a spirit, as Shade experienced. the Tree is also a portal for the living that sends them back to the surface world. As Shade, Yorick, Murk, Nemo, and Java entered the Tree to become spirits, Goth returned to the Jungle Pyramid, and Griffin and Luna returned to Tree Haven.

Pilgrims are bats who travel the Underworld, telling bats to go to the Tree. Frieda Silverwing, Yorick, Murk, Nemo, and Java are all pilgrims.