I want to greet my closest people in Klingon saying:
Greetings noble friend, we shall purify our bane with the gentle bath of our enemies' blood!
Thank you for any help where to start
Klingon doesn't have the word "greetings", nor a verb meaning "be noble", so the first part isn't really possible. Klingons don't tend to use greetings like Humans do.
Can you explain what "our bane" is? Is that "things that annoy us"?
If so, maybe something like this would work:
jupwI', nuQwI'ma' watlhchoHmoHmeH DoQmIv'a"e' tebbogh jaghma' 'Iw wIlo'
My friend, we will use a bath filled with the blood of our enemies in order to cause our "annoyers" to become pure

Qapla' appreciate it