What is the song playing in Naruto Shippuden episode 121 when Itachi and Kisame are walking together? In Naruto Shippuden episode 121, it starts playing at 0:40 or so when Itachi and Kisame are walking together.
The song you're referring to is Itachi's theme song. https://www.youtube.com/watch?v=AXLfg2ry_F4