Here's the speed increase jutsu for Kigen's boomerang along with another technique that i've been thinking about
Name: Bu-Meran Katana Sumiyaka Kazou Jutsu (Bu-Meran Katana Speed Increase Technique)
Rank: C
Type: Ninjutsu
Element: Wind
Description: This jutsu is used in combination with Kigen’s Bu-Meran Katana. In order to perform this jutsu, Kigen will first channel his chakra into the chakra conductive metal of his boomerang and form the Bird hand seal. This will cause the chakra in Kigen’s Bu-Meran to slightly amplify the power of his throws and increase Bu-Meran’s overall speed by 50% for the next 5 posts. Once the time limit is done, this process will have to be repeated in order to achieve Bu-Meran’s increased speed. (Therefore, in order to sustain this jutsu Kigen must repeat this process every 5 posts or else the Bu-Meran will fall back to its original speed.)
Link: none yet
Name: Shippuu Bu-Meran Jutsu (Hurricane Bu-Meran Technique)
Rank: C-S
Type: Ninjutsu
Element: Wind
Description: This jutsu can only be used while Kigen’s chakra is channeling through the Bu-Meran and Bu-Meran Katana Sumiyaka Kazou (Bu-Meran Katana Speed Increase) is active. First, Kigen will make the hand seals of the Bird, Horse, Dragon, and then Bird again. After this, Kigen will throw his Bu-Meran with both hands at the target. Once the Bu-Meran has left his hands, a cylindrical tornado will form around the Bu-Meran. The tornado will be roughly 4.5 feet wide and 8 feet high. Note: The reason Kigen must have the Speed Increase Jutsu active and the reason he must throw with both hands is because at this level Kigen does not have the necessary skill to achieve the speed and power this jutsu requires without using both hands and amplifying the power of his throw.
Therefore this jutsu will change stats and requirements as Kigen reaches new levels:
B rank-Must have Speed Increase Jutsu active, but only requires one hand. Tornado dimensions become 10 feet high and 5 feet wide.
A rank-Must have Speed Increase active, only requires one hand. Tornado dimensions become 15 feet high and 6 feet wide.
S rank-Only needs Kigen’s chakra channeling through the Bu-Meran (no longer requires Speed Increase Jutsu to be active) and requires at least one hand. Tornado dimensions become 30 feet high and 15 feet wide.
Link: none yet