Thanks for alle the answers. I'm currently decidingt between a rogue or a warlock. The warlock would be a Tiefling, the rogue might be a Drow. I already have the wood elf ranger and I will play her too - I'm normally doing a lot of playthroughs, if I like a game. The Gith mage isn't off the table too. I know, that we have every class but ranger as companions, but I think, it is ok to have two of one sort. I never play fighter so that class is out for now.
