This is an illusion

[Reaper]

The enemy would lose their sight meaning they couldnt aim there jutsu.In some cases they coud with their smell/hearing I guess but thats rare

 

[Adachi]

Yes, and if he particularly trying to aim a move, say, like Kirin, or a directed weapon, he would not be able to hit you. xD

Spoiler

( Kokuangyo no Jutsu ) - Bringer-of-Darkness Technique
Rank: A
Type: Supplementary
Range: Short-Mid
Chakra Cost: 30
Damage Points: N/A
Description: The user makes one handseal, causing the opponent to believe they have been trapped in a world of infinite darkness, where their sense of sight is useless. It is capable of affecting multiple targets within range. However, it does not negate their other senses.

Well, I think that's it for Genjutsu.

 

[Reaper]

Thank you Adachi <3