Arrow-kun

Arrow-kun are wandering spirits taking the form of sentient arrows in the UKSRT universe.

Personality
Arrow-kun are generally mischievous, and enjoy messing with people. Despite this, they are easy to tame and can serve as lackeys for anyone willing to go through the effort.

UKSRT2 - Stepmania Fever
Arrow-kun appear in Sneaky Spirits, filling in for the spirits. They disappear when shot at.

They also appear attached to the arrow you shoot Ayaze with in the final step of Flugel.

UKSRT 3.0 - You Can (not) Hit Arrows
Arrow-kun appear as the "undead arrows" for target practice in Night of the Undead Arrow, again, disappearing when shot at.

They also make an appearance during the spellcard "Rinascita - Souls of the Damned", during the extra stage.

UKSRT4
One of the Arrow-kun appearing in Octotoxin seems remarkably similar to Ayaze.

ArrowQuest
Arrow-kun are working for Ayaze, and kidnap Chan's girlfriend Ashe.

Trivia

 * Arrow-kun are based on Mungyodance's Worm noteskin.