Hi folks,
HERE I found an offline version of unicast, which is a mod that let you to change your costume, appearance, etc. locally. I use it on Menma's TERA and it works just fine.
To install it just extract the "unicast-100" folder into "\Menma's TERA\proxy\mods".
In game, type "/8(space) u ui" to open the menu.
Check
the devs page to support them.
Idk if they can ban you for using it, so use at your own risk.