i personally consider it an simple Energy Effect - kinda like a campfire, and not magical at all. magic can, however, suppress or resist or abate it (obviously) - as wearing a ring of fire resistance allows one to walk thru said campfire, but the effect itself (in 10e) is simply energy. how the misty DM wants to run it in his 'verse is up to him
that being said, there ARE a few energy types in the big 10e list that are quite obviously magical in nature. Mana, Dragonfire, arguably Psionic and possibly Force would all be flavors of magic. in most cases tho, magic is merely the conduit which allows you to CHANNEL such energies and manipulate them into a form of your choosing.
in some TSR book somewhere, it talked about that being the logic behind reagents - the ball of guano and sulfur a wizard uses to call into existence a fireball serves as a kind of counterbalance or tradeoff to the elemental plane of fire. the ball of energetic material goes to the fire plane and a correlative amount of burning flames appears here.
so, in Cloud’s game - magic may be whats bringing you the energy in the first place, or letting you twist it around your weapon… which would be shut off inside antimagic whats going to be interesting is to see how he plays it the first time you attack a natively antimagical sneakypants…
