One-Punch Man: Boros’s Second Form Power Attack

One Punch Man (Anime) Chapter 12

 

One of the attacks used by Boros during his second form generates an explosion powerful enough to damage his own ship. While it has no effect on Saitama, it had previously destroyed every opponent Boros had faced.

This raises a key question: how powerful is Boros’s attack, really?

Here, we attempt to provide a reasonable estimate, based strictly on the information and visuals presented in the series, without contradicting the narrative.

One Punch Man Chapter 35

To estimate the yield of the explosion, we first need to determine its diameter. Fortunately, the visuals show that the explosion spans roughly the full width of Boros’s ship, giving us a clear reference point.

One Punch Man Chapter 35

The problem is that no official dimensions for the ship are provided in either the manga or the One-Punch Man Encyclopedia. Attempting a direct scale from the manga panels would be highly uncertain and unlikely to produce reliable values.

For this reason, we instead rely on Genos’s notes, shown in Episode 12 of the anime adaptation, which provide sufficiently credible information to support a reasonable estimate.

One Punch Man (Anime) Chapter 12

According to Genos’s notes, Boros’s ship measures approximately 9,230 meters × 15,024 meters. (translation of Genos' notes)

Based on the nature of the explosion—which generates a pressure wave strong enough to bend metal structures and breach the ship’s armor—we can apply the Hopkinson–Cranz scaling law, using the Glasstone & Dolan / Kingery–Bulmash airblast model.

The formula is:

$$Y = \left(\frac{x}{0.18}\right)^3$$

Where:

• Y = explosive yield in kilotons of TNT

• x = blast radius in kilometers

• 0.18 = empirical constant associated with severe damage to metal structures

Using the explosion radius (x ≈ 4.6 km):

$$Y = \left(\frac{4.6}{0.18}\right)^3 \approx 16{,}853\ \text{kilotons of TNT}$$

This corresponds to roughly 16.8 megatons of TNT.

This value should be treated as a minimum estimate, since the explosion shown appears even larger. Even so, it fits well within the narrative scale of the series and remains consistent when compared to Metal Knight’s missile barrage. Even using conservative assumptions, Boros’s attack reaches the multi-megaton range, powerful enough to damage a massive alien warship.