This tree is mysterious and doesn't have much info to document.
The only known info is that Sagians are born from this tree. From information coming from some Sagians, they remember seeing a Sagian inside the tree when they were born to the world and hear echoes in their head when they touch the tree but can't make out their appearance.
Another piece of info is that it is known to give energy to all of the Sagians. Without it, the Sagians would lack powers and won't be able to transform into their Relic Form. The device is related to the tree; it gives the Sagian energy and can also cause the Sagian to change appearance. As said on the Relic Device page, sometimes, the Sagian doesn't need the device to transform, but it happens rarely.
Was it the first thing that was born in Sariju? Who is the mysterious Sagian living inside? There has yet to be more info documented. It's still a mystery.
Trivia:
None.