The Devil Butler - Vol. 4 Ch. 514

[MangaDex]

 

[lior05]

I don't understand something...
If they had these ethereal experts the whole time, why did they even bother going to war with Tianyu for years when they could easily overwhelm them?

 

[Glomoro]

I don't understand something...
If they had these ethereal experts the whole time, why did they even bother going to war with Tianyu for years when they could easily overwhelm them?

Tianyu has its own ethereal stage experts. It's like the mutually assured destruction between two countries with nukes. Both sides were at least hesitant to let their ethereal stage people off the chain for fear of how much damage they would do to everything around them while fighting.

That's also why these three weren't even going to do anything at first unless they had to. The more they do, the more likely they are to be discovered by Tianyu side's ethereal people before the goal was achieved.