Why has the shadows changed?

Ten Desires was like:

Let's give shadows to the main characters and enemies not:

DDC also did this, but all the main characters have blue shadows!!!

 Sakuya is the only fitting character with the blue shadow.

Until Legacy, when ZUN said: "Hey, let's give the shadows to the enemies now"

The enemy shadows actually follow the DDC style of shadows (same color for each boss).

Junko and Hecatia doesn't have shadows.

And then....

"Hey let's do the same thing for seasons" said ZUN.

I bet that Touhou 17 will have shadows for the main and enemy characters, and they go all about with the shadow colors

I'll make a follow up to this soon