Do you need separate game clients for Neverwinter?

Played Age of Conan/The Secret World, and they needed separate game clients. Install, copy to x new folders, link Inner Space to each.
I haven't seen it mentioned, but is Neverwinter different - needing only one client? Can it be either the Steam version or the Arc version?

[lax]

No, you do not need multiple installs, for pretty much any game. I don't think you can use the Steam version to multibox, and I wouldn't recommend it if it worked because it would add extra layers of annoyance to just logging in.