More than likely a bit feat. In this particular chapter, Tohru and Kobayashi discover that the mountain where they first met has been defaced.
And the culprit is Ilulu.
The series takes place in the Saitama Prefecture, so to find out which mountain it could be I looked up mountains in the Saitama Prefecture. Thankfully, there are only four.
God only knows how I decide which one it is, so I'll just calc all four!
We never see her destroy it or how, we just know she did. It looks like a pulverization to me since there's nothing left of the section destroyed, but I'll calc fragmentation and v. fragmentation for each mountain as well just in case. Hell I'll even do vaporization since this is a dragon and it may very well have been a fire-based attack.
Here are the pixel measurements for reference. Each of the mountains' Wikipedia pages only list their heights, so I'll have to use scaling for the radius.
Also for reasons I, to this day, fail to understand, I'll have to multiply every cm^3 value I get by 1000000. Apparently.
419/168 = 2.49404761905
88/419 = 0.21002386634
175/419 = 0.41766109785
Mount Bukō[]
2.49404761905 x 1304 = 3252.23809524 meters for the diameter of the base of the whole mountain.
0.21002386634 x 1304 = 273.871121707 meters for the height of the part which was destroyed.
0.41766109785 x 1304 = 544.630071596 meters for the diameter of the part which was destroyed.
Volume for a cone is pi*(r^2)*(h/3)
V = pi*(273.871121707^2)*(272.315035798/3) = 21389110.3239 m^3 or 2138911032.39 cm^3 for the volume of the part which was destroyed.
Fragmentation[]
((2138911032.39 x 1000000) x 8)/2 = 8.5556441e+15 joules or Small City level
Violent Fragmentation[]
((2138911032.39 x 1000000) x 69)/2 = 7.3792431e+16 joules or City level
Pulverization[]
((2138911032.39 x 1000000) x 214.35)/2 = 2.2923779e+17 joules or City level
Vaporization[]
((2138911032.39 x 1000000) x 25700)/2 = 2.7485007e+19 joules or Island level
Mount Kobushi[]
2.49404761905 x 2475 = 6172.76785715 meters for the diameter of the base of the whole mountain.
0.21002386634 x 2475 = 519.809069192 meters for the height of the part which was destroyed.
0.41766109785 x 2475 = 1033.71121718 meters for the diameter of the part which was destroyed.
Volume for a cone is pi*(r^2)*(h/3)
V = pi*(516.85560859^2)*(519.809069192/3) = 145415579.066 m^3 or 14541557906.6 cm^3 for the volume of the part which was destroyed
Fragmentation[]
((14541557906.6 x 1000000) x 8)/2 = 5.8166232e+16 joules or City level
Violent Fragmentation[]
((14541557906.6 x 1000000) x 69)/2 = 5.0168375e+17 joules or Mountain level
Pulverization (Accepted)[]
((14541557906.6 x 1000000) x 214.35)/2 = 1.5584915e+18 joules or 372 megatons of TNT or Mountain level
Vaporization[]
((14541557906.6 x 1000000) x 25700)/2 = 1.8685902e+20 joules or Island level
Mount Kumotori[]
2.49404761905 x 2017 = 5030.49404762 meters for the diameter of the base of the whole mountain.
0.21002386634 x 2017 = 423.618138408 meters for the height of the part which was destroyed.
0.41766109785 x 2017 = 842.422434363 meters for the diameter of the part which was destroyed.
Volume for a cone is pi*(r^2)*(h/3)
V = pi*(421.211217181^2)*(423.618138408/3) = 78705126.6096 m^3 or 7870512660.96 cm^3 for the volume of the part which was destroyed.
Fragmentation[]
((7870512660.96 x 1000000) x 8)/2 = 3.1482051e+16 joules or City level
Violent Fragmentation[]
((7870512660.96 x 1000000) x 69)/2 = 2.7153269e+17 joules or City level
Pulverization[]
((7870512660.96 x 1000000) x 214.35)/2 = 8.4352219e+17 joules or Mountain level
Vaporization[]
((7870512660.96 x 1000000) x 25700)/2 = 1.0113609e+20 joules or Island level
Mount Ryōkami[]
2.49404761905 x 1723 = 4297.24404762 meters for the diameter of the base of the whole mountain.
0.21002386634 x 1723 = 361.871121704 meters for the height of the part which was destroyed.
0.41766109785 x 1723 = 719.630071596 meters for the diameter of the base of the part which was destroyed.
Volume for a cone is pi*(r^2)*(h/3)
V = pi*(359.815035798^2)*(361.871121704/3) = 49061538.1219 m^3 or 4906153812.19 cm^3 for the volume of the part which was destroyed.
Fragmentation[]
((4906153812.19 x 1000000) x 8)/2 = 1.9624615e+16 joules or Small City level
Violent Fragmentation[]
((4906153812.19 x 1000000) x 69)/2 = 1.6926231e+17 joules or City level
Pulverization[]
((4906153812.19 x 1000000) x 214.35)/2 = 5.2581703e+17 joules or Mountain level
Vaporization[]
((4906153812.19 x 1000000) x 25700)/2 = 6.3044076e+19 joules or Island level
Conclusion[]
If vaporization is accepted for any of the four or pulverization of Kobushi is, Kanna gets an upgrade as she should easily be as strong as Ilulu's casual strength. Otherwise it's a nice bit feat I suppose.