Getting Started in Lords of the Fallen

There's no single best class — all 10 are viable to finish the game, they just set your starting point, not your ceiling.
The Condemned class is the traditional souls-like hard-mode option, starting with the lowest total stat points — pick it only if you want the toughest possible start.
You can't respec your class after character creation, so if you want to try one of the 4 unlockable classes, that requires starting a new character.
Radiant-scaling weapons are considered some of the strongest early options, including a fast, pure-radiant short blade obtainable from a boss relatively early on.