This achievement is story-based and cannot be missed. After you kill Victor, the last boss in the game, the achievement will unlock.

During the first part of the battle, ignore Victor and use remove curse on the Doge and then beat him up. Repeat this three times to end the fight.

In the Twilight World, keep rolling from the energy balls Victor fires at you and get close to him, so that you can use your weapon to attack him. Once you kill him in this form, there will be yet another part in the real world where you are up against Victor's human form. Use your weapon of choice, keep rolling from his attacks and utilize your "Passage" skill to disappear and reappear with a back attack.