Data Ravelさんのイラストまとめ

When the third Holy Stone was destroyed the figure of a huge dragon appeared. Black War Greymon felt a big power from that being, and think that it's its real opponent.

The result would be a world of darkness born from the destruction of all worlds, including the Digital and Real worlds. The only way for them to prevent that to happen is to protect the Holy Points, the Holy Stones.

However, there are other worlds like the Dark Ocean or ones that they don't even know what they are.

If the Digimon are appearing in the Real World, then the distortion in the Digital World must be getting worse. The distortion is when the balance between the Digital and Real worlds is lost and they starts to fuse as one.

When Iori asked a reason for why they appeared, Miyako explains that in the past it was believed that Kyoto was protected by four animals, and was a place close to other worlds and spirits appeared, temples were created on the four directions to protect the it from Demon Gates

So, whether it's a demon world, a strange world or simply any other world that isn't the human world, Kyoto may be familiar with that. So the distortion and the Digimon may have affected Kyoto more than Tokyo.

In addition, to protect the capital of "Demon Gates" important temples and shrines were built. It was imagined that evil spirits would appear if this was not done.

Miyako was thinking about why Digimon appeared in Kyoto, Haruhiko said that due to its nature as capital, Kyoto always had an affinity with spirits. His job was to find the truth behind Yōkai's stories. Kyoto was the capital due to its land being suitable for the four gods.

Before Black War Greymon existence distorted the world everywhere Black War Greymon was, now that the Holy Stones are being destroyed, this distortion grows bigger and now Black War Greymon and other Digimon are appearing in the Real World.

After that the Holy Stones are introduced as these mysterious rocks that protects the Digital World and has a huge effect on the Digital World. When Black War Greymon destroys the rock the world loss its balance.