The only improvement I could have seen is forming the request as a question. "Would you please let Nazuna kill Colibris?"

Americans (At least in smaller communities in the northwest and south, can't say for areas I have not lived in) typically ask you to do something, then depending, act upon it.

For example; A good boss might remind someone about incorrectly filing their paperwork by saying, "Hey, would you mind making sure you put X file in Y place? Thanks!"

Whereas if the same boss said, "Put X file in Y place." it can come off as rude.

Please, thank you, not being demanding and acknowledging people are world wide I think.

Your English is very good OP, also, I'll try my hand at JP and say.

ありがとうございます。

Politeness is always appreciated.