Gathering Form and Scattering Energy can be used for traveling, but it's only suitable for short distances.
Stopping to admire special scenery, pausing at the sight of unfamiliar monsters—walking and stopping intermittently—it took nearly a day to travel from Watchtower Port to the desert. Finally finding Tassera, Leon obviously wouldn't turn around and leave after just one fleeting night.
To put it another way, the thought of spending such a long time flying back, with nothing particular waiting for him at home, left Leon feeling drained, unwilling to move, and only wanting to collapse on a bed.
Tassera continued her research, delving into the Bloodsucking Sword forged by a Yugros Demon, while Leon lounged in her study, planning to brush up on his knowledge of Yugros Demon lore.
