TO translate directly, it's 黑暗军团 or 暗黑军团, but here the meaning of "dark" is 黑客 for sure. 所以在翻译的时候，我们有“直译”和“意译”两种。 When we do 直译, we focus on its literal form. While we emphasise its meaning in "意译".

I don't know what "dark traveller" is but you're overthinking. The reason why 黑客 sounds like "hacker" is because it might be a loanword (I'm no sure). Translation and a word's actual meaning are two different things, so you can't use the same theory.

没错，是“黑客军团”。 That sentence is 我想加入黑客军团

There is the same question you can take as a reference. https://www.quora.com/What-is-the-best-way-to-translate-Dark-Army-the-fictional-Chinese-hacker-force-from-Mr-Robot-into-Mandarin#MoreAnswers I will say“暗黑军团” “我想加入暗黑军团”