This is actually a bit annoying to calc due to the shape, and it's not exactly clean, so I'm gonna do 2 shapes.
Cylinder, and Ellipsoid.
So basically, Riokku (210 cm) punches Hibiki (180cm) Through a Wall, likely concrete because they are in a school building. Here's the scan for their height.
Cylinder Formula (Accepted)[]
Here's the pixel-scaled image. Can't use this one since I don't really have anything to scale it to and the angle is a bit weird.
Dude's height = 210 cm, divided by 610 gives us 0.344262295... cm for each pixel.
Diameter = 270 pixels x 0.344262295 = 92.950819672cm for diameter, 46.4754... cm for radius.
Wall thickness = height = 18.24590 cm.
Plugging the values into this calculator, we get 123811.63 cm3 for volume.
Fragmentation of Concrete = 6j/cc
123811.63 * 6 = 742869.78 joules, or 742.8 Kilojoules (Wall level)
Ellipsoid Formula[]
Here's the pixel-scaled image.
Each pixel is 0.344262295 cm.
Longer diameter = 270 pixels x 0.344262295 = 92.950819672cm for diameter, 46.4754... cm for radius.
Shorter radius = 26.33606557377
Wall thickness = 18.24590 cm.
Volume (Elliptic Cylinder): (Pi*46.4754*26.3360)*18.24590 = 70159.76 cm3
70159.76 x 6 = 420958.5 joules, or 420.9 Kilojoules (Wall level)