So I was requested to do a calc for some stuff.
Reference video for everything. (all feats happen between 6:32 and 6:50, scaling uses some later instances after 18:28 as well)
I will do the 4 requested feats one after another when I have time.
Feat 1: Speed of the monsters beams[]
Picture 1
Picture 2
Picture 3
Ok, the last two steps of scaling were easy enough to find, but the anime actually was able to make it so that in the whole fight scene between Dante and the demon-guy not a single direct comparison between sizes was made. He also had some inconsistent sizes for artistic reasons, but in the end I think I found a screenshot that depicts his size quite well.
So, we start with picture 1.
Here we see dante close to the camera and the monster further in the distance. Now that isn't good for scaling since dante will in relation to the demon of course appear bigger than he is, so we use a little trick.
One can see two spikes, one in the foreground dante is standing on and one in the background beside the demon. I completet the form of the spike in the foreground to how tal it would be without being broken. From there I will scale that spike and one can quite safely assume that the one in the background is the same size. From the spike in the background I can then scale the demons shoulder width (specifically the width between the pointy end of his shoulders). So lets start:
I assume Dante is around 1.8 m tall.
1.8 m = 185 px = yellow line
9/925 = 1 px
504 px = 4.9037837837837838 m = pillar height = pink line
pillar height = 194 px = blue line = 4.9037837837837838 m
1 px = 0.0252772359988854835 m
224 px = shoulder width = red line = 5.662100863750348304 m
picture 2:
Shoulder width = 5.662100863750348304 m = 53 px = pink line
1 px = 0.106832091768874496302 m
382 px = green line = top thingy of building height = 40.809859055710057587364 m
picture 3:
top thingy of building height = green line = 30 px = 40.809859055710057587364 m
1 px = 1.360328635190335252912133 m
349 px = 474.754693681427003266334417 m
Video is running in 24 fps, the feat happened in 1 frame.
474.754693681427003266334417 m / (1/24) sec = 11394.112648354248078392026008 m/s = Mach 33.160979768
So High hypersonic attack speed for that beam. (note that beam speed changes, so don't scale to characters)
Feat 2: Speed of lightning part 1[]
I don't know if that may not be even real lightning, but lets just calculate the speed that it is depicted with.
picture 4
So in picture 4 one sees the lightning I will calc. One doesn't see the top of the building well in that frame so I will use picture 5 (which is edited picture 3) to calc the distance to the top of the building.
Picture 5
30 px = green line = top of building = 40.809859055710057587364 m
1 px = 1.360328635190335252912133
577 px = blue line = distance lightning traveled = 784.909622504823440930300741 m
The animators gave the feat once again not more than 1 frame, so:
784.909622504823440930300741 m / (1/24) sec = 18837.830940115762582327217784 m/s = Mach 54.824886322
So High Hypersonic+ for the lightning.
Feat 3: Speed of lightning part 2[]
Picture 6
So this time lightning going upwards from the clouds.
blue line = earth radius = 785 px = 6371000 meter
1 px = 8115.9235668789808917 m
71 px = 576230.5732484076433107 m = green line = distance lightning crossed
Feat once again took 1 frame (really the authors of that series seem to love 1 frame animations):
576230.5732484076433107 m / (1/24) sec = 13829533.7579617834394568 m = Mach 40248.934103498 = 0.046 c or 4.6 % of the speed of light.
That would be Sub-relativistic.
That result is probably unrealistic and an outlier. Interesting enough to have a lightning calced above lightning speed, though.
Feat 4: Cloud stuff[]
So we have the clouds extending in that one scene so lets see what that would mean for energy.
I modified the last scaling again.
So 1 px = 8115.9235668789808917 m as before.
If one looks closely the cloud has already extended a bit before the extension scene, so that part has to be subtracted. For that I have drawn the purple line for the extension on an image of the original extension and then laid that image with transperence above the other one.
Before scaling I will have to make a guess in cloud thickness. Looking at figure 1 here (∆z = cloud thickness) it seems that 500 meters is a safe low end.
Lastly I will assume that all the clouds extending extended with the same speed. (reason for this is mostly that I do not want to calc it with integrals)
Now the scaling:
229 px = yellow line = full extension = 1858546.4968152866241993 m
π*1858546.4968152866241993^2 = 1.085167388998385611686e13 m^2
purple line = 154 px = 1249852.2292993630573218 m
π*1249852.2292993630573218 ^2 = 4.9075780014655924118049e12 m^2
1.085167388998385611686e13 m^2 - 4.9075780014655924118049e12 m^2 = 5.9440958885182637e12 m^2
Volume = 5.9440958885182637e12 m^2 * 500 m = 2.9720479442591318e15 m^3
Cloud density is 1.003 Kg/m^3
2.9720479442591318e15 m^3 * 1.003 = 2.9809640880919092e15 kg
The clouds extended in 21 frames, so timeframe (21/24) seconds.
Distance = 1858546.4968152866241993 m - 1249852.2292993630573218 m = 608694.2675159235668775 m
608694.2675159235668775 / (21/24) = 695650.5914467697907171429 m/s
0.5*2.9809640880919092e15 kg * 695650.5914467697907171429^2 = 7.2128859606897939305436988e26 J
Continent level clouds... k.