So what does -localdataonly actually do? Does this mean that every time when i try to run the game it uses files from stardocks server?

And is this -localdataonly only applies to this game or is it general command for all win apps or whatever? Just trying to get my head around it..

are you playing this game? If you are have you tried to enable the missing spells? Was looking for bug report on this but didnt find any on the forum, so either no one noticed it or its too minor to be reported.

Well ragarding the spells "Aura of Might" is one of the city buffs that increase your troop base stats when they are built in the town with the spell cast in it. When you conquer enemy town you can see in town detail windows that there some buufs there, so it means that the buufs cast by AI sovereign stay active even after you taken over its town and you can cast same buff again which does stack with previous one. So i guess its one of the bugs that need to be addressed. I've found out about "Aura of Might" when i was looking up details of the town i was about to conquer. The AI sovereigns are able to cast those spells, then i decided i'll play around with xmls to see if i can make them work my self, because obviously they are working for AI. While i was going through CoreSpells.xml i compared "Aura of Vitality" spell definition against "Aura of Might" and "<AutoUnlock>1</AutoUnlock>" was missing. There are others spells that aren't accessible,like "Glyph of Life", "Destroy Land", which are missing same tag and "<prereq> tag..Its either poor copy and paste work or this is beta and not everything is suppose to work, so that why i haven't reported it as a bug yet and i'm too lazy

I'm new to this stuff so could you be so kind and explain to me what "vanilla game" is?

Heavenfall if i add -localdataonly will the game stop connecting to the beta server? I mean will i not need to login? Because when i changed my nickname here on forum i had to add "nickname" and "password" commands to my game shortcut to be able to play the game again otherwise it would give me error, saying that login details are wrong.

Vanilla is the game with no mods or changes by the user. It is also referred to as the core game. A mod is like adding flavors. I like to think of Heavenfall's mods as Chocolate Lover's and mine as mint chip. But mostly there is just a connection between ice cream and modders. 

Just found out from the Magic.pdf that not all spells show up in all games..And some of them have to be researched through tech, which isn't in every game as well. So it's not a bug, but still sad.