Oriole

This truly… surprised Roy.

At first, he thought that this was impossible. How could a demon open a Gate of Heaven? But after reading through Xeron's memories, he found out that this was real!

The Gate of the Abyss and the Gate of Heaven were ultimately just a kind of spatial teleportation magic. The only difference was that opening a Gate of the Abyss required building a magic formation with demon characters, and opening a Gate of Heaven required building a magic formation with angel characters.

In the millions and millions of years of continuous usage by angels and demons, these two types of spatial magic had long been very, very mature. The patterns, characters, and incantations needed to construct the magic formation had almost reached an unchangeable level. In simple terms, it was simply foolproof. As long as you engraved the magic formation correctly, you could activate it by inputting a bit of magic power.