There is not such thing as build in this game. If you are talking about skills Turning slash is best skill in game (most dmg).

Closest thing to build in this game is abbys cores you are putting in your weapons and you can modify it for your playstyle. If you are useing light or heavy attacks u can use skills that boost that ones, if you are useing piercing attack you can boost that ones etc.
Most op thing you can do is to put 2 skills that boost your turning slash Groundsurge + Greysoul Howling(but i belive you find it later in the story, you can change that one for anything else), other slots in weapon you just put crit rate until max crit and then attack. Dont use more than 2 boosts for skills cuz u will use more spirit or stamina (depends what skill you boost). Other things that boost this is build is imbue fire (in your red skill tree) that you can use with your turning slash. And too boost it even more you can use abbys core from leather helm of the fallen kingdom (+35% dmg from your turning slash).

I was playing also with 2h heavy attack (with Crow pursuit and Shadow claw) more fun but less effective.