You can complete the game by entering new game plus. When you complete the game without resting at a bonfire or dieing you will be rewarded with two special rings, these rings will make your left hand and right hand weapon invisible, however, animation features can still be seen e.g twinblade spin effects. To get the right hand ring invisible you will need to go into new game plus without resting at a bonfire, for left hand, go into new game plus without dieing.