do you think a breath player (knight specifically) could use their wind powers mixed with some fire based weapon like a flamethrower or simple lighter, and "fan the flames" so to speak, making like those big fire tornadoes. I mean I know John's windy thing put out fires, but I also think with careful application it could make fires bigger! using oxygen as fuel and whatnot.

Fire and Lava Tornadoes are both things the Wind pulls off in Homestuck, with the Lava Ones being John’s doing, so this is definitely plausible. Also his “They wait” description mentions about him fanning flames whilst blowing candles, soo.