How tall are the killers exactly?

The Nightmare is actually 5'9. The female legion members are 5'5, or at least Susie is. Susie's a sophomore, and sophomores are usually 15, and the average height of a 15 year old girl is 5'4-5'5. If Joey and Frank are also sophomores then they're 5'5 or 5'6, average height of a 15 year old male is usually 5'5-5'6. But since the new killers didn't come out by the time you wrote this ill write em: Ghostface is 5'10 in the movies, in game demogorgon is about 6'8 since hes as tall as the doors and the average door height is 6'8. But in the show he's 18 ft. But before I get into the others, lets look at comparing heights. Ghostface is up to the trappers torso, and when you compare 6'3 to 5'10 the 5'10 person is up to the other persons chin. So either trapper is taller than you said or ghostface is shorter in the game. Clown and huntress are both 6'5, but in game the huntress is taller, so either the huntress is taller than you said or clown is shorter than you said. In game clown and the doc are about the same height. Huntress is slightly taller than the doc. But the shape and huntress are the same height in game (Which would make sense because Michael is taller than Doc in game), so if Michael is 6'8 so is the huntress. If Billy is actually 5'11 than I'm wrong about ghostface being 5'10 in game. Billy is a lot taller than him. I'm only 100% certain about legion, demogorgon and the ghostface.

I‘m pretty sure that the female legion members are the same height as the male ones and even Susie is actually taller than the male survivors. Also frank is 19 and not 15.

Oni is one inch short of 6 foot, which is where all of his anger and rage comes from

You can usually find canon heights for the licensed killers, though I'm not sure how true to these the DbD models are:

• Micheal Myers (Shape): was 5' 10" in Halloween (1978) / 6' 7" in the mid-2000's Halloweens / 6' 3" in Halloween (2018)

-Weirdly enough, his model seems to be closest to his most recent appearance's size, despite his inclusion in DbD pre-dating that by two years. Otherwise he would be about the same height as Freddy and Ghost Face.

• Leatherface: Either 6' 2" or 6' 4" in Texas Chainsaw Massacre (1974)

-Height listed depends on where you look (though his actor was the latter height).

• Freddy Krueger: 5' 9.5" when played by Robert Englund (original) or 5' 5" when played by Jackie Earle Harley (2010 Reboot)

• Pyramid Head: ~6' tall in Silent Hill 2 / ~7' tall in the Silent Hill movie. Add an additional 2-3 feet for the size of his namesake headpiece) He's currently the tallest character model in DbD.

• Amanda Young (Pig): Around 5' 3" (her actress's height) in Saw (2004). Possibly with a few extra inches for the pig-mask.

• Ghost Face: Supposedly 5' 10" in the original Scream (1996). Though he's a costume played by so many people that he probably doesn't actually have one canon height.

• Demogorgon: Can apparently be between 6-10' tall according to Stranger Things lore. Though the one in the show looked to be on the shorter end of that range (probably around 7 ft tall).

And just because I found this hilarious:

• Ash Williams: 6' 1" (his actor's height)

-This means Ash should actually be taller than all of the Average-height killers.

I'd guess that all of the "Tall" killers are around 6-7 feet tall, while all the "Average" killers are more like 5-6 feet tall. It's also worth considering whether you're going for body height or total height, as some killers gain length from hair, hats, and headdresses (Spirit, Oni, Plague), while others noticeably hunch/slouch (Hillbilly, Clown, Demogorgon).

This picture seems accurate. If we assume that Freddy is 165cm (Jackie Earle Haley height), we have the Wraith standing at 198cm and the Demogorgon at 220cm (the distance between every line in the background is 5.5 cm)