When, on your Arietta/Aria/Acqua, running perl interpreter, you receive the following warning:
perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LC_CTYPE = "UTF-8", LANG = (unset) are supported and installed on your system.
that means the target system doesn't have all the locales, that the client is sending into the environment of SSH session.
Rather then install unwanted locales on the target, the client configuration can be changed in order to avoid to send all the locales.
For example, if your client is running Linux, comment out the following line into the /etc/ssh/ssh_config configuration file.
SendEnv LANG LC_*
Of course you have to logout and login again into the target, in order to make the change effective.