With all of the strange and amazing anime weapons to choose from, one might not expect an anime character to zero in on needles - but actually, there are plenty of anime characters who fight with needles out there.
Some anime needle users have a far more straight-forward approach to battle than others do. Gintama's Oboro pretty much just throws needles at people's weak points. Other characters get a whole lot more complicated, however. Illumi Zoldyck of Hunter X Hunter isn't just trying to open up holes in people - he actually inserts needles into people's brains in order to control their behavior. Still, other characters can eject needles from their bodies - Jiraiya from Naruto can turn his long white hair into a mass of sharp, projectile weapons.
Needle-based attacks are surprisingly versatile, so let's give them the attention they deserve.
Chelsea is a member of the Night Raid, a group of assassins. She approaches her battles from the shadows, preferring not to be seen while she hurls sharp needles at precise points in her opponents' bodies, intending to destroy them with a single shot. She might also creep up behind someone and attack them from behind.
While most anime needle users simply throw them at people, Illumi Zoldyck's needles have a much wider range of abilities. When he implants his needles into another person, he can control their behavior, alter their appearance, and even control corpses. Notably, he implants a needle into his younger brother Killua's brain in order to force him to run away from battles that might put him in danger.
Though better known for techniques like sage jutsu and rasengan, Jiraiya also uses needles to help him out in battle - specifically, he hardens his hair and wraps it around his body, then shoots out razor sharp strands at his enemies. This technique is effective for both offensive and defensive purposes.
Himiko Toga uses needles in a fairly unique way. Rather than trying to cause injury through needles, Toga uses them to drain her opponent's blood into a syringe, which she can then use to activate her quirk, Transform. With Transform, Toga can take the physical form of anyone whose blood she ingests, which is great for undercover missions with the League of Villains. She can also use knives to obtain the blood she needs.