The Eight-Finger (エイトフィンガー Eito Fingā) is a Sitar that can be wielded by Demyx in Kingdom Hearts 358/2 Days. It can be upgraded to the Eight-Finger+.
The Eight-Finger has a strange shape, with a headstock that slants downward to the diagonal right. It has a small, circular notch on each of its sides. It is lavender with light blue inner edges. The neck of the sitar is rather short, is blue on its left side and light blue on its right. The body of the sitar is vaguely triangular in shape. Its left half is lined by three navy blue spikes that angle upward sharply and decrease in size the higher up they are on the instrument. The Old Hand’s body is navy blue with light blue edges. It seems to have two white stings anchored to the body by as a triangular, silver piece. The Old Hand sitar only differs from this one in coloration.
Eight Finger is referring to a technique of playing guitar in which the guitarist use all four fingers of both hands to tap the fretboard.
Eight-Finger's ground combo starts with a quick leap forwards, thrusting the sitar diagonally upward, followed by Demyx performing a 360° spinning diagonal slash with the tip of the sitar. The next move of the combo is a quick thrust of the sitar diagonally upward, the combo then ends with four quick blasts of yellow shockwaves in an outward direction.
The aerial combo consists of a series of very fast airborne spinning attacks, followed by a blast of three yellow shockwaves forwards.
 See also