My interpretation of the lighter color was just that it was due to the light from the fire and the flame itself. Given that he's blasting the barrier, most of the kicked up dirt would be blown back at him in that ground level backwash you talked about, not thrown straight up, and judging by his face in the last panel, he's more sooty than muddy.MuonNeutrino wrote: ↑Fri Jul 07, 2017 7:48 pmTo me, most of that looks like dirt and dust that got kicked up - note the tan color of most of it. Only the darker backwash at ground level actually looks like smoke to me. And like I said, I wouldn't be surprised if the energy release managed to flash-burn the grass in front of him or similar, but I strongly doubt that that could have used up enough oxygen to be dangerous.Ddraig wrote: ↑Fri Jul 07, 2017 6:56 pmIf it gives off that much smoke, it's not 'merely' energy release - that's fire. Sooty fire, at that. Either wood or gas/oil (not lamp oil). Self-oxidizing fires tend to not give off (much) smoke, I'm not sure of the exact chemical reasons, but that's what I've seen. Of course, energy has to be released in some form, it's not too absurd that it'd be released in the form of fire. It'd be like trying to go really fast without traveling in any direction.
The dark in the smoke is generally carbon soot and ash that got entrained and incompletely burned, usually the less oxygen a fire has the smokier it is.
I also want to note that talking about the form of energy release is a bit confusing. In this case, 'fire' wouldn't be the *form* of energy release, it would be the *consequence* of energy release. The energy release here is not coming from combustion, it's coming from mana. Said energy may well raise the temperatures of materials exposed to it by enough that they catch on fire, but that'd be an effect, not a cause.
Energy isn't some physical thing that you can just conjure into being, it's a general property of particles and matter. It needs a carrier, even if that carrier is something considered an 'energy particle' like photons are for radiated heat.
"Releasing" energy is the act of it transitioning from one particle to another, either in the case of chemical reaction (e.g. fire) or physical reaction (e.g. kinetic impact or heat transfer). Here he's deliberately conjuring an explosion, so I can only assume that magically works by conjuring whatever components are missing (really just fuel and heat, since he'd always have had oxygen available before). Given how smokey it is, I think it's a safe assumption he didn't conjure the oxygen to go with it, and the size of the flame rather exceeds any I'd see from just grass.