All Seeing Darkness

This technique is the strongest genjutsu of Kogomei Nara. Using natural energy, with Yin and Yang chakra, she creates a miniture moon, then covers it in her Shadow Forest technique, causing it to emit not light, but darkness. This darkness ensnares anything it covers in a genjutsu. Unlike light, which can penetrate solid, non-transparent objects, this shadow-light, can penetrate all objects. The only dojutsu capable of resisting its effects are the Byakugan, because of the way it functions.

Within the genjutsu, everything is viewed as a silhouette. Kogomei can attack from these silhouettes, as well as merge with them. She's a living genjutsu within the genjutsu itself, being unaffected by techniques. In this genjutsu, a dark moon rises in the west, and sets in the east, repetitively. The moon used to cast the genjutsu is absent, making the feat of breaking the genjutsu from within the genjutsu impossible.

The only way to break the affected out of this genjutsu is to destroy the minature moon construct, with has the ability to absorb ninjutsu and senjutsu, so pure natural energy attacks are needed to harm it. And even then, multiple attacks are necessary, as the construct is highly durable and can take a lot of damage before being destroyed.