Killer Concept---The Entity

HatCreature

The basic idea for this killer is what I'll call the ''Traitor'' Mechanic. The mechanic is basically turning a Survivor into a temporary Killer.

The Entity
The Entity's power is ''Corrupt'', at stage one of the match The Entity cannot physically harm anyone but instead must siphon off blood from Survivors by Corrupting one and temporarily forcing them to attack another Survivor. After the Corrupted puts one Survivor into the Dying state they are released from their condition and turn back into a normal Survivor. While Corrupted, the Survivor is unable to heal, repair, or sabotage until they force another Survivor into the Dying state. Each hit that a Corrupted lands feeds The Entity blood allowing it to use its main weapon, the black insect-like arm we see on the hooks. The blood is a blow-by-blow thing, if a Corrupted lands one hit then The Entity has one hit available and so on. The balance is that The Entity cannot attack a Survivor while they have an active Corrupted

A Corrupted Survivor has no distinguishing features showing that they taken over by The Entity, the only time they are revealed to no longer be an ally is when they attack which morphs their arm into a black insect-like claw that reverts to normal after an attack. While The Entity has Corrupted a Survivor it can temporarily see the Auras of other Survivors that its Corrupted has been in close proximity with.

Perks for The Entity could include allowing more than one Corrupted at a time, allowing The Entity to attack while a Corrupted is active, etc.

Add-ons could be multiplying the amount of hits per strike by 2, 3, etc. Extending the proximity to a Corrupted to show the auras of other Survivors, etc.

This concept is basically an introduction for the Traitor mechanic that could be used. Instead of being Corrupted a Survivor could be Possessed or Mind Controlled, instead of The Entity it could be a Hypnotist or Demon, etc. I just think this would introduce a new level of challenge to the game by forcing Survivors to temporarily become the enemy and a huge incentive to being under this effect would be earning Blood Points for each strike against another Survivor, that way it isn't a hassle to hurt your friends but also a sadistic gift. And the whole thing is about not knowing if your friend is actually the enemy until it's too late. I really love necromancer classes so this concept really jumped at me because it's kind of the same idea but instead of resurrecting the dead you're using living people as your puppets.

Peasant

While your idea is certainly a creative one I am afraid that it simply wouldn't work for a few reasons. The biggest problem is that survivors are sacrificed to the entity by all killers as a means of killing them in most matches. Having the entity as a killer means that there is no logical need for sacrifice as it'd be hooking survivors up for, itself? Furthermore the lore states that the entity feeds off of the hope of the survivors. Since it can be assumed that the majority of survivors possess some knowledge of the entity upon seeing the entity as a killer would destroy all of their hope which would in turn render killing the survivors pointless. Then there's the nature of killers. How exactly would the Entity play? Each completed sacrifice with other killers shows the survivor being grabbed by the entity and taken into the sky. Therefore if you play as the entity you would have a top-down architectural view of the level and you'd be every where at once. This is understandably unbalanced as most of the in game obstacles are designed to block vision horizontally, not vertically. This is ignoring the fact  that you would also logically be able to hit survivors anywhere on the level once you have "blood". Then there's the corruption mechanic. I'm sorry but this idea is simply terrible for Dead by Daylight because of the variety in the game's players. When you play Dead by Daylight you meet all kinds of people. Some are clueless novices that just bought the game. Others are experienced players that like the game and just want to have fun. There are also plenty of toxic players who are naturally sadistic. Your corruption mechanic would likely annoy veterans, confuse new players and only be enjoyed by toxic players. This would ultimately disable unity amongst survivors which in turn would break the game as survivors are supposed to be able to work together. There is a good reason why their icon is interlocking gears. Your perks are also ill-advised as they only work on the Entity and are useless on all other characters. To put it bluntly, playing as the entity would not make sense lore-wise and gameplay-wise. 

It's good to see that there are creative people in the community but the entity is an all powerful god that just doesn't feel right to play as.

However, your necromancer might work in other ways.

First-off you would need a killer with a background with the dead. Maybe a graveyard watchman who robbed graves?

Next comes your necromancy. The killer's power could be simply put "Raise Dead". The power "Raise Dead" can be used on survivors that have just been sacrificed or killed. This power turns resurrected survivors into zombified versions of themselves that have a limited life span. I personally would give the zombies a lifespan of a little over 1 minute and 30 seconds. These summoned zombies would have no perks and instead just a timer icon where there perks were. The zombies would also be forced into a first person perspective like all other killers. They would essentially function as a perkless hag without traps. This would also sit better with the community as rather than have a teammate randomly attack you out of nowhere instead they are punished for letting a teammate die. While a zombie is "alive" the main killer should recieve a debuff to speed and attack cooldown as there are now two killers. The power's add-ons would revolve around increasing the time the zombies are around and how many can be active at once as well as buffing the main killer's abilities during a zombies lifespan to counter the debuffs. 

Since being given a potential Ally after a sacrifice or kill is so powerful this killer will inspire new levels of camping. This is why the perks should discourage camping. Here are my ideas.

Respect for the Dead
When the killer is (48/40/32) metres away from the hook the sacrifice time is accelerated by (3/6/9%).

Watchman
When a survivor gets within (2/4/8) metres of a hooked survivor, receive an audio notification and their aura is revealed to you. Cooldown would be (60/45/30) seconds.

Vendetta
When a survivor is unhooked from 32 metres away or more, receive a (0.2/0.4/0.6) speed boost for (1/2/3) seconds. 

I apologise for any spelling errors but I typed this on my phone. I really like your idea of a killer that possesses survivors but playing as the evil that killers sacrifice to just feels wrong. I hope that you can see where I am coming from. And I wish you the best of luck with your goal of getting a necromancer into Dead by Daylight. Feel free to use my killer idea as your own as up until now I hadn't even thought of a killer such as this.

HatCreature

I can see where you're coming from, no matter what you change the Corruption would always be overpowered because it would compliment the killer too much. Maybe not in mechanics but for the game as a whole it would be too easy for the killer because no one would trust anyone and everyone would always die because there's no teamwork. 

Oh well, I thought it was cool because it was more creative in design than slowing someone or running fast, throwing an axe, etc.

Global

thought it's not friendly it would be amazing to play as the Entity.