Really newbish battlefield spell question

[Amhazair]

Most spells of that type do indeed affect both sides of the battle. The one example that comes to mind that only affects your enemy is Curse of Stones. (and the army-wide buffing spells only affect your own troops obviously)

In any case, the manual should be quite clear on who is affected I think. If it says 'everyone' or 'the entire battlefield' that's exactly what it means.