Tenebra was originally located in Brazil, but CipSoft decided to move it to the USA on April 2005. The reason that the Brazil server was moved, was because the Internet provider couldn't ensure a proper and stable connection to the game server. You can check out the news about Tenebra's moving for CipSoft's official words about it.
The word Tenebra derives from "Tenebrous", which means "Scary, Creepy". It may also derive from "Tenebrae" which is Latin for "Shadow". "Tenebra", in italian also means "Darkness". Tenebra is also the godess of night, darkness, dwarves, undeads and creatures of night and underground.