Despite having a rather extreme case of near-sightedness, due to the damage caused by her flames when she awakened them, Karna turned out to be a rather cheerful young girl. As long as no males were too close to the pale girl, which wasn't really much of a problem considering that having the Infinite Demi-Dragon Goddess or said Demi-Dragon Goddess's mate nearby was a great idiot-repellent. The few idiots that did manage to get too close quickly learned to back off when their robes randomly started to burn, with flames that were way too hot to be a mere Fire-Making Spell.
A rather humorous incident caused by Karna's flames setting something on fire involved an argument between the worm, the cockroach, a few ants that were backing up the two and the rest of their class as witnesses. Blake and Karna had been enjoying a nap on a hill near the groundskeeper's house when the worm and cockroach made their presences known as the two argued on the way to a lesson, though what subject it was wasn't something that either Blake nor Karna were concerned with. Had someone seen the two from below the hill they would have been treated to the rather adorable sight of the two girls enjoying their nap peacefully, with Karna using Blake's exposed abdomen as a pillow.
"I suggest that you two either keep it down or take your bickering elsewhere." Deadpanned Blake at the arguing bugs without opening her eyes.
"Or what, mudblood!?" Shouted the worm, clearly still lacking survival instincts.
"Yeah! What are you gonna do about it!?" Shouted the cockroach.
"I won't say this again. Leave. Immediately. You're starting to irritate me, bugs."
"Please make the idiots leave. I'm starting to lose my control again." Begged Karna in a slight whimper. The bugs seemed to not have caught on that an uncomfortable Karna caused stuff to spontaneously combust into initially solar-classed flames. After the initial ignition, Karna's solar-classed flames quickly cooled down to the heat of normal fire, if there was anything left to burn as whatever the flames initially touched burned away very quickly.
"WHO THE HELL ARE YOU CALLING AN IDIOT!?" Shouted both the cockroach and the worm in unison.
"EEEEP!" That was the sound of Karna waking up with a startle, accidentally flaring her magic and as a result accidentally setting both the cockroach and worm's clothes on fire with solar-classed flames. Almost instantly turning their clothes, except for their embarrassingly printed boxers. The cockroach had a pair with the Hogwarts crest printed all over them while the worm had a pair with a rather strange acronym printed all over them. And that acronym was C.F.S.
Whatever that acronym stood for, it was apparently funny as pretty much everyone nearby ended up laughing at the two bugs' embarrassment. Blake and Luna let loose a few snickers when Blake informed her mate about the incident and when Luna told her what the acronym stood for. When Karna asked what the acronym meant, the only answer she got was that she would understand when she was older.