File:Popori gang.jpg

Summary
not sure what is original source. Taken from https://stopgame.ru/blogs/topic/89222 (2018-07-12) There are copies in various sites. Including https://wallpaperset.com/tera-wallpapers which has various loading screens and promotional images.

It's likely promotional released by Hangame, En Masse, or Gameforge/Frogster


 * found in En Masse Full fansite kit screenshots https://web.archive.org/web/20171230050329/tera.enmasse.com/community/fansite-kits

It's freely available promotional picture from En Masse.