Just bought Grim Dawn.

I’d recommend you check out the guide I posted if you’re just starting out. There are several decent beginner builds linked there as well as lots of tips/info to get a good understanding of the game. That said, there’s something to be said for a blind play through to discover things for yourself.

But as far as developing a first character, there’s lots of good info there. Personally, my first character was a Witch Hunter, followed by a Witchblade. I’ve completed Ultimate with both, starting from scratch, so they’re certainly viable (and fun!). Here’s the link to the New Player Knowledge Compendium.