best class for game completion?

The best class I would say would be demon slayer or if you wanna start now Bm. But some advice, I've done everything in this game from power lving for money to fm hoeing wasting time. One of the hardest/most rewarding thing you can probably do is making one of the best guilds in your world. MS isnt a game about completion in any sense you can always be better/have more/do more/do it faster.