Mastery
Researching how to replicate spatial transportation over a long distance was certainly not easy.
Even though it got a lot easier when he retrieved a bunch of useful runic devices that he had used in the past, not even the teleportation device of the Old Elf Crevian could answer a bunch of questions.
It was necessary to use spatial-attributed mana to start and finish the creation of the teleportation devices, and particular runic solutions were needed. To create the runic solutions, one required more than ten spatial-type ingredients, and the use of spatial-attributed mana that had been diffused with mana, amassed, and purified.
Nial had once asked Master Crevian about the creation process of those long-distance teleportation devices similar to the one he had used when he returned from the Alliance City, but the answers he received had been quite displeasing.