Voice allows the user to increase the volume of their voice, giving them the ability to create loud, high-pitched sounds.
The sound that comes from Hizashi's mouth can reach extremely high levels, enough to incapacitate people by disrupting their eardrums (which may cause bleeding). The loud noise will also drown out other sound-based Quirks, giving him an advantage against those Quirk types in battle.
Using Voice too much can cause Hizashi to get a sore throat, and he has a disadvantage against people who can go underground, since sound doesn't travel underground very well.
Because sound does not travel underground very well, it's ineffective against anything moving through it.
Hizashi wears a special Directional Speaker System support item around his neck area that allows him to direct his sound waves. This prevents his Quirk from affecting allies that are close to him.
Named Super Moves
- Hizashi uses his Quirk for the first time in the U.S.J. Arc in the anime, while in the manga he uses it during the Final Exams Arc.
- Unlike most others, Hizashi's Quirk is a rare example of a Quirk manifesting right after birth, along with the Luminescent Baby.
- In the anime, the words shouted by Hizashi will travel alongside Voice's sound wave, which is depicted in a yellow color. In the manga, the speech bubbles that are used through Voice have double borders.
- Human voice - Wikipedia article about the specific sound source Hizashi's Quirk is based after.
- Loudness - Wikipedia article about the specific property of sound that Hizashi has actual control of.
- Sonic weapon - Wikipedia article about sound being used as weaponry.