Can't sleep, so I might as well make a post.
I've been pondering ways to add some flair to Irui's Genjutsu scheme, and in his dialogue I found he asks lots and lots of questions, and is a bit naive, so this could become a signature of his. Here is what I propose as a UA swap for Ravenous:
Spymaster Words have power, and Irui may use them in his Genjutsu. By asking the opponent a question, he may use the sound of his voice, in the form of a question, to trigger Genjutsu. Whenever an opponent answers or acknowledges a Spymaster question, Irui can snare the opponent in these sound-based genjutsu, as his voice is processed by the brain.
Spymaster: Questions don't have to be answered, sometimes they're never heard, or out of range. Spymaster techniques can not be used to initiate self-harming actions . Spymaster techniques are also restricted to one target at a time, each target requires concentration, and due to the delicate nature of this trigger, cannot exceed B-rank. Like traditional genjutsu, sources of intense pain, and chakra transfer will break the technique.
I borrowed bits of the Brainwashing Quirk from MHA, and some bits from Tower of God. Unlike the Brainwashing Quirk, it doesn't allow full body control, rather its a Genjutsu set up, and even then its limited in Rank.
Im just trying to figure out what his "signature" will be.