Genjutsu within NBRP follows a couple rules. Let's say you cast an A-rank Genjutsu. You then proceed to cast a B-rank one, the B-rank one would add onto the A-rank one. But they have to be in that order. If you cast a B-rank, then an A-rank, the B-rank is comepletely nullified by the A-rank. As for the release of Genjutsu, it depends on your rank, and which level of Genjutsu you can disperse. Here's how it corresponds:
( Genjutsu: Kai ) - Illusion Technique: Release
Rank: C-S
Type: Supplementary
Range: Short
Chakra Cost: 15-40
Damage Points: N/A
Description: The user does one hand seal to focus and then proceeds to disturb his chakra flow by forcefully stopping it momentarily and then "spiking" his spiritual energy, unbalancing his chakra. This dispels any genjutsu set upon the user except MS Eye Techniques, Paralysis-like Genjutsu and Demonic Illusion: Toad Confrontation Chant. The effectiveness of this technique is dependent upon the skill of the user. A Jounin rank ninja can dispel Genjutsu up to C-rank. An S-class ninja can dispel Genjutsu up to B-rank. A Sannin rank ninja can dispel Genjutsu up to A-rank. A Sage rank user can dispel Genjutsu up to S-Rank. The user may use this technique through physical contact on others to dispel them from Genjutsu. The technique can only be used once per turn and the user still needs to fully follow the logic as to why he figured out it was an illusion.
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You can also break it by Pain method, although, it depends on the rank;
D Rank Genjutsu: Chipping a Finger (like one does as he bites to draw blood for a Summoning Jutsu)
C Rank Genjutsu: Low level Physical Attacks, Bitting a chunk of your Cheek
B Rank Genjutsu: Low ranked Taijutsu/Freestyle
A Rank Genjutsu: High ranked Taijutsu, Stabbing Yourself in minor muscle, Cutting yourself, Breaking Smaller bones, Low level Burning/Voltage, Painful Cold
S Rank Genjutsu: EIG/Sage level Taijutsu, Breaking Bones, Deep Stabs or cuts, Medium Voltage/Burning, Extreme Painful Cold, Bitting your tongue off