User blog comment:B214/Question and Answers 4/@comment-24502975-20141102214513/@comment-24502975-20141103005135

You know what, nevermind. I just remembered that Devils make contracts with magicians to research magic to improve the Underworld's technology, so like the barriers placed around Auros and such, Devils' teleportation magic-circles are built by magic with custom house crests placed on them and is activated through the use of demonic power. As for how they work, perhaps they have a built-in ability that uses demonic power to locate the exact coordinates.