Demon King KE calculation

The four story building is 12 meters in height, which is 145 pixels.

0.08 meters per pixel

For the head I'll use sphere calculator.

r = 55 pixels

Vvolume = 356.8 meters3

For the neck I'll use cylinder volume calculator.

h = 38 pixels

r = 30 pixels

Volume = 54.2 meters3

For the arms I'll use cylinder volume calculator.

h = 442 pixels

r = 61 pixels

Volume = 2555 (5110 for both arms) meters3

For the ribcage I'll use sphere calculator.

r = 102 pixels

Volume = 2226 meters3

For the lower part of the body I'll use cylinder calculator.

h = 82 pixels

r = 45 pixels

Volume = 264.6 meters3

And last but not least - the legs, for which I'll use yet again cylinder calculator.

h = 340

r = 63

Volume = 2136.2 (4272.4 for both legs) meters3

Collective volume is 12284 meters3

Now, for the mass I'll use human density, which is about 985 kg/m^

Demon King's mass = 12099740 kilograms

As for velocity, Meneldor is as fast as Will (228.8 m/s, Subsonic+) and Demon King should definitely be at least as fast as Meneldor (Meneldor himself mentions he is nowhere near Will's level). But to avoid calc stacking, I'll use baseline Subsonic+ speed.

KE = 0.5*12099740*154.35^2 = 34.45 tons of tnt, City-Block level