I think this one was good, It was reasonably balanced for the an ability without much risk. You can comment your idea the poll of Nen Type. I'd like to know your suggestion for his ability.

Well, Even I won't use it, if not for a reason.

I almost forgot

No, There is a chance since he envied Alluka for having Killua's affection. We could just say being with Akira since he was Killua's friend will give him an idea of how to get along with his beloved brother.

Yeah, Even if Mereum died and she lost her king. With her personality either she will take revenge or just die with him.

If I'm going to pick, Maybe Koala or Cheetu, Koala has lost his motivation in his life and Cheetu has a childish personality. But still, I can't give up Pitou😖 easily. If I can't think of a good reason and logical situation for Pitou to join them, I don't have a choice but to give up on her, huhu!

Yeah, In other words, She would do everything for the sake of her king.

Yeah, she won't normally but with her turmoil of mind that she betrayed the spider in exchange for rescuing Chrollo or going against the rules it's possible. I hope so –_–

Yeah, There is a love interest.

About that, I don't know if it's not only Zoldyck move. But regards to Most of Meteor City knowing it, I don't think so, Since Feitan background story wasn't revealed yet. And I think Canary learned it after meeting one of Zoldyck Butler or both of them learned it through someone else related to Zoldyck something like Kikyo since she also came from that place. I don't know anyone except these two who use rhythm echo besides Killua.