Webkokushibo is the demon with the most blood demon art techniques at eleven describe forms, though it is suggested that he knows at least sixteen.
Akaza comes next with ten,.
Webthis page contains known demonstrations of blood demon arts in the series.
Webthis deadly blood demon art allows akaza to manipulate shockwaves and thoroughly integrate them into his fighting style.
Webboth are his blood demon techniques called hakai satsu or destructive death, though yes the compass needle is the secret behind akaza, and it the most powerful defense.
Webakaza's blood demon art (low posting) [manga spoilers] the compass resembles koyuki's hairpin:
Akaza's blood demon art techniques.
All of his attacks are named after.