Back when v2.7 finally got its preview livestream we saw Kuki start her teaser by taking off her mask. Since her name literally means ninja I jumped on this move after years of training by Gaijin Goombah's Which Ninja series. I even joked that I might have to do another Which Ninja topic to talk about what Gaijin would undoubtedly attack right away.
Now that she's been released it's pretty easy to see what's going on. She's not a ninja just disguising herself as one. And while her name does still mean ninja it is also a fairly common name in Japan and the word for ninja also means to endure so in modern times it doesn't have to relate to ninjas. Her abilities are all based on her shrine maiden upbringing and I'm not sure if any of you guys noticed it but I think her attacks actually might have let us figure out what Naku Weed are based on.
Introducing the Yachi Torikabuto or Aconitum. Just like how Kuki describes the Naku Weed this flower is a potent neurotoxin meaning it'll paralyze you. Worse it can stop your heart. So why would a shrine maiden know this? Most toxic plants and animals have been incorporated into medicine. For example a very popular modern day toxin would be botulinum toxin otherwise known as Botox. In Chinese herbal medicine which Japan adopted you can use Yachi Torikabuto or in Chinese 乌头 Wutou and 附子 Fuzi and is used to reduce inflammation and slow heart rate among a bunch of other applications.
Medicine like this usually comes from folk remedies which could come from things like religious rituals so it could be that Naku Weed as a Narukami Shrine evil repellant that brings good fortune was developed into a paralyzing agent. Maybe Kuki got some tips from the Shuumatsuban. And because of that we come full circle because ninja like the Shuumatsuban would be very adept at the use of poisons. Also if you look at what Kuki says on your birthday she gifts you a Naku Weed tipped dart and tells you to use it carefully. I guess we're ready to take on the Fatui in Sumeru. 
Tips and Tricks from a Super Casual Genshin f2p
