Contrary to popular belief kunai are not the same as throwing knives, nether is it their primary purpose to be used as one. They were primarily tools, secondarily short bladed weapons and tertiarily throwing weapons.
When thrown, it was with the intent to distract, disorient or disable rather than to kill since the damage would likely be insignificant due to the lesser mass and smaller blade.
That being said, this is Blade and Sorcery. Here they are implements used to flex your superior skills to the AI as you go about your rampage :)
Sped up slow motion was used!

MODS:
Medieval Megapack U12: https://www.nexusmods.com/bladeandsor...

MUSIC:
Flex Music Dramatic Violins:    • Royalty Free Time Lape Music | Dramat...