Interestingly, in Lithuanian mythology, “Ragana” is the Goddess of Trees.
So I suppose the game is Raganarok Online. 
More seriously, however, Lithuanian mythology does have a world tree, and regards oak trees as sacred symbols. If “Savior” is interpreted as a Christ-like figure, then it’s not too much of a stretch to presume that the Tree of Savior is closely related to that figure, especially considering how loosely Ragnarok Online follows Norse mythology.
But then, plot twist! The tree is not evil, but the other tree is, after all! 
Seriously though, calling it “tree of savior” makes little sense to me.
[quote=“dracohandsome, post:22, topic:320”]
If “Savior” is interpreted as a Christ-like figure, then it’s not too much of a stretch to presume that the Tree of Savior is closely related to that figure, especially considering how loosely Ragnarok Online follows Norse mythology.
[/quote]So… in the sense of new religion (=Savior) forcibly pushing away the old one (=the gods that suddenly left)? This could actually make sense.
Maybe its called tree of savior because it was the only thing left by the godess. The godess were the saviour or somethin thus tree of saviour?
But if the tree was left by the gods, it sure didn’t save anyone - the intro is talking about many lives being lost due to the tree and the monsters that came from it.
It could go all Crystal Chronicles on us and say that it’s a savior to the monsters who regard humans as their boogeymans.
i wonder if it will just as good as Ragnarok
Perhaps we are the monsters and the tree is saving the world by cleansing us with its spawn