As you see, the pacman package installs the the launcher, which then proceeds to download and install the actual browser in your home directory.
This is unusual, the Tor Browser works this way.
Is there any data you want to save (bookmarks, logins) in your Tor Browser?
If not, just rm -rf /home/fenris/.local/share/torbrowser/
and start again.
Nevermind, I read again and you say the problem started before on its own.