Rangers start out as underpowered, and then start going up, eventually reaching godlike levels of overpoweredness by the end. I'm talking in the range of 50,000 damage from a single attack (albeit spread out to several targets). Nothing in the game comes close to that amount of HP, even on Nightmare skills.
Specifically, invest heavily in Splitting Arrow, Way of the Ranger, and Death Blow, and pump points into both Dex and Intelligence, and you'll be on your way to breaking the game and making it cry.
Amdusias is the first hard boss in the game, and there's another unpleasant fight on Sentinel Island as well, but it shouldn't be too hard after that.
