Lizard Tail Splitter allows Setsuna to split her body into several pieces and control them telekinetically.
Setsuna is able to split off pieces from any part of her body. Those cutoff bits of hers move around by floating, following Setsuna's will. Due to their usually small size and high speed of movement, they're hard targets to hit individually.
Notably, if any of those pieces contain a functioning organ, said organ is capable of operating by itself away from the rest of her body, allowing Setsuna to, for example, speak with just a floating jaw that contains her mouth, or see with just one quarter of her face, as long as it has one of her eyes on it.
There's a limit on how long one of Setsuna's cutoff segments may stay away from her body. Once that limit is reached, the aforementioned segment will stop functioning altogether. Setsuna is able to regenerate lost segments, but there's a limit in that process as well, which forces her to regroup scattered body pieces (which can be exploited to locate her position) after she becomes unable to regenerate them.
Setsuna is currently able to divide her body into 50 different parts depending on the length.
Lizard Tail Splitter can be used for spying (By separating parts of her eyes to get multiple viewpoints) and long range combat. Setsuna's individual parts by themselves are said to be weak, but are difficult to defend against due to being small targets.
- Autotomy - Wikipedia article about the biological process that is the basis of Setsuna's Quirk.