Wisdom Tree Moak.
Wisdom Tree Moak (3-48, 50): Moak is a tree spirit that serves as the Gingmen's guide and advisor. When the Balban attempted to harvest the energy of the Ginga Forest to revive Daitainix, Orghi the elder of Ginga Forest Village gave Bokku an amulet to take to the Gingamen before he and the entire Ginga Forest were turned to stone. When the amulet was opened, a seed was found inside that the Gingamen planted at the ranch where the father of their friend Yuuka arranged for them to stay which instantly sprouted into a giant tree. Hearing a voice speaking though both their Ginga Braces and from inside the tree, the Gingaman investigated and were pulled into an alter like room inside the tree where Moak introduced himself to them.
As a tree spirit, Moak is able to sense events over great distances by communing though the "Network of Trees," allowing him to sense and alert the Gingamen to all Balban movements. If an area has no trees however, it creates a blind spot where his senses cannot reach. As his title suggests, Moak also has an encylopedic knowledge of all Ginga legends and further aides the Gingamen by teaching them how to unlock their full power and supplying them with new weapons. Near the finale, he sacrifices himself to prevent the birth of the Earth Beast, but left behind a seed which was planted in the revived Ginga Forest and sprouted into a new Moak.