"There are times when Natsu becomes very strong due to 'protagonist buffs' or the power of friendship and emotions, but fundamentally—as a fixed definition—Natsu cannot beat Laxus in a one-on-one fight. He also cannot beat Gildarts one-on-one, and he cannot beat Erza. That is the definition I've set"
I think i finally solved the mystery. Maybe everyone here including me overreacted, as it's not something new, he also said that Laxus was 1000 and buffless Natsu was 600 before. The secret lies on
protagonist buffs. These buffs don't even need to be temporary, actually the protagonist buffs don't even need to be uncommon.
Mashima is the kind of person who would say Goku is weaker than Majin Buu because he would disregards super saiyan forms as protagonist buffs, no matter how natural they are to Goku. So when Mashima says that Natsu is fixed as weaker than Erza, Gildarts and Laxus, he is talking about this Natsu
The Natsu who gets defeated by human Fire and Flame mages. This is the regular Natsu, notices that he is just using the basic Fire Dragon Slayer Magic
here.
Even FDKM is a protagonist buff, actually since Alvarez it was considered a protagonist buff. When Hiro said that Laxus was 1000, buffless Natsu was 600, he said that Gray was also 600, but it was Standard Devil Slayer Gray and Base Natsu
You guys can check the
chapter, no FDKM spell was used in their fight at avatar. FDKM already scaled above Gray and was considered a protagonist buff. If he was stronger or not than people like Laxus and Gildarts with that it's another story, but the form itself already don't needs to follow this
fixed definition that Mashima put. For example i believe that Base Natsu was weaker than Erza, but with FDKM he was already stronger than her, but weaker than Laxus and Gildarts in the Alvarez context. In 100YQ the power dynamics of the protagonist buffs varied as they got stronger, even Erza leveled up to Laxus and Gildarts level, so the fixed definition with Base Natsu as weaker than them, remained, but his regular buffs being weaker or stronger than them varied.
This version of Natsu should be considered FDKM despite not having named attacks in this situation because of how strong he was. A protagonist mode at worst if you refuse to name it FDKM without a spell.
But what i mean is that, in the end of the day, the statement is meaningless as even LFDM can be regarded as a protagonist buff