It's "Ride on Time" by Tatsuro Yamashita. This specific arrangement is done by @Monotonemonkey on Twitter for SiIvaGunner's upcoming KFaD2 tournament.
This is my favorite song in this event so far. I'm so excited to see if we get a full version in the future!
This is my favorite song in this event so far. I'm so excited to see if we get a full version in the future!