The Tribe discovered the Fountain long ago, long enough that the specifics are lost to myth and legend.

It grants great power... at a price.

Submerging yourself within the fountain gets you a chance at magic that is at least loosely aligned with what you request.

The price: you are flung out into the wider universe experiencing whatever adventures suit the fountain. You may return and empower the tribe with your gifts after your trial is complete which is never less than a decade but is sometimes far longer... assuming you survive at all.

The Garden's lesser gifts allow for healing and interrealm travel.