The Trail of Souls is the "bridge" between Mira and the rest of the world. Travelling through the Trail of Souls must be very careful, as if someone gets out of it, he or she could be stuck in another dimension forever.
Role in BKO[]
Although it can't be crossed in the game (as it is impossible to travel to Mira), at the end Sagi and Milly cross it in the Sfida in their way to Balancoire.
Role in BKEW[]
After getting the End Magnus of Anuenue, the group decides to travel to Mira in the Mindeer, King Ladekahn's private liner, for obtaining the fourth End Magnus. But while crossing the Trail of Souls, they are ambushed by the Goldoba, who shoots down the Mindeer, getting the heroes stuck in a separate dimension. Luckily, they are helped by The Great Mizuti and get to Mira safely. Later in the game, one may travel to the Phantom Goldoba, which appears in the Trail of Souls.