Fidelius charm

The Fidelius is a spell to hide the knowledge of an object.

## Effects

The charm hides a stretched location between ward stones tied to an object in said location. People who somehow stumble into the Fidelius location get confused and when they are near the Fidelius location, they completely forget of the existence of said charm.

Space in the Secret can't actually be sensed or detected. For instance, Harry used a Fidelius to hide from Sirius and Shacklebolt and was undiscovered when the used area of effect spells (casting chalk dust to try to find an invisible person).

The Fidelius Charm appears to keep the secret location hidden even from tracking magic, such as the Wand Trace or a Taboo Jinx being triggered within it, such as the one placed on Lord Voldemort's name after the Fall of the Ministry of Magic. In 'Deathly Hallows', Harry and Hermione say Voldemort's name on 12 Grimmauld Place several times unaware of the Taboo, yet when the Death Eaters appear in the square outside, they are still not able to see the house. This directly contrasts the result of Harry saying the name while in the tent, which was followed immediately by the enchantments and charms placed there disappearing and a team of Snatchers Apparating outside. Additionally

The Fidelius doesn't stop working with the death of the caster or secret keeper (based on the Fidelius cave that Harry and Daphne find on the dragon preserve).

## Incantation

The incantation for the Fidelius charm is Fidelius Occultum.

## Usage

To make a Fidelius place, you need to place wards to set up a perimeter and then cast the charm. It can take up to several minutes and you finalize the charm with the incantation. Caster may need to use Occlumency so that the caster knows all detail of location to be put under Fidelius charm.

## Limitations

The spell can be applied by strong mages and one mage had a limited amount of Fidelius charms they can cast because casting the Fidelius uses part of the caster's soul and thus it limited the amount. Fidelius is soul magic. A Secret Keeper is assumed to only be able to hold up to seven active secrets. This is Harry Potter's limit and the limit is assumed for other based on horcrux rules (max number times you can split the soul is seven).

The secret could be revealed by saying the secret, someone reading the secret on a piece of paper or using a spell within the fideliused area and someone seeing it coming out of it.

Only the secret keeper can tell the secret to someone who doesn't already know the secret. This means non-secret keepers can try to tell the secret as a check for Polyjuice impostors and listening charms; if there's someone listening who doesn't already know it then they're not capable of saying it aloud. You also can't write down a secret unless you're the secret keeper, which they used to identify messages from themselves that they didn't remember sending.

One of the theorised weaknesses of the fidelius charm is that the more you knew about the area under the fidelius, the stronger its power was. By knowing less, you could technically faster find about it than someone who knew more.

Divination magic, like Daphne's Eye of Killrogg spell, can penetrate the Fidelius.

It is presumed that the Secret must be true in order for the Fidelius to remain active. For instance, "The Potters live at Potter's Cottage in Godric's Hollow."; the Fidelius would be broken if the Potters died or the house was destroyed (there was no longer a Potter's Cottage).

## Known casters

* Harry Potter

* Albus Dumbledore
* Lord Voldemort

## References

Book 1 - RiBSR - Ch. 15 - The First Year's Train Dance,

Daphne Greengrass mentioned that to Tracey Davis during the train ride.
Book 1 - RiBSR - Ch. 3 - Flying Under the Radar - Gold,

Harry Potter uses the spell for the first time in the series.
Book 1 - RiBSR - Ch. 3 - Flying Under the Radar - Gold,

Harry Potter making a fast fideliused area to save himself from a dragon.
Book 2 - TFoP - Ch. 35 - Bonus - Blood Money & Blood Magic,

Harry Potter realized he could only hide seven fidelius locations.
Book 1 - RiBSR - Ch. 10 - The Book of Names - 2/2,

Harry Potter explaining the limitations of the fidelius charm to Daphne Greengrass.
Book 2 - TFoP - Ch. 29 - Cleithrophobia and Planning a Heist,

Harry Potter explained how to breach Albus Dumbledore's fideliused mirror.