Dream

"Two titans, Arun and Shara ... came together, dreaming of peaceful world."

The Dream in TERA refers to dream of Titans Arun and Shara. Once leaving their old realm, they created a new one. Arun and Shara fell asleep, and together dreamed of a more peaceful world. The Gods are among the first to emerge from their dreams.

It should be noted that Arborea and anything that lives there is not a dream, but a dream become reality. If someone dies, their souls are said to "return to the Dream", which is also used as a threat.

What happens then. It's apparent that powerful beings can revive someone from the Dream. This seems trivial task for Gods. Akasha revived Karascha, Lakan revived Dakuryon and Darkan.

There are some efforts by mortals to do the same. Scions of Lok tried to revive Samael, but were not powerful enough to do that in time. Also the Scions have tried to bring back god Lok, as have servants of Dagon tried to bring back their god. Also Sikandaris tried to bring back Sikander, before Thulsa and Killian took advantage of this.