直到世界尽头

Missing, extremely new, or very obvious to obtain.

Probably a reference to the song, "世界が終るまでは…" (Until the End of the World). It is the eighth single by Japanese band WANDS. The song expresses deep feelings of longing, loss, and the pain of a love that seems unreachable or has ended. It can sort of relate to Arkeri, who yearns to explore new places and see new sights.