Chapter 3 of the Gate - Thus the JSDF Fought There! manga is titled, "Tuka and Flame Dragon"

Plot

In her unconscious state, a female elf began to recall what had happened before the Third Recon Team saved her from the well. A Flame Dragon appeared unexpectedly over the village of Koan when Tuka Luna Marceau was sleeping. When Hodor Rei Marceau told her to flee, she decided to take up arms instead, claiming that having another able warrior would be better than trying to escape from the virtually inescapable Flame Dragon.

The battle was a one sided slaughter. The elves were taken out one after another by the great beast, whose scales prove to be impenetrable by the elf weapons and magic. Finally, an arrow shot by Hodor, in trying to save Tuka, managed to hit and blind the Flame Dragon in the left eye. Realizing that he had actually enraged the dragon, Hodor pushed Tuka into a nearby well where she stayed until the bucket thrown down by Itami Youji hit her right on her forehead and knocked her out as a result.

The Third Recon Team put in their best efforts to try and resuscitate the unconscious female elf. Most of the members though, like Kurata Takeo who had his camera at the ready, simply gawked at the fantasy creature, which earned them the ire of Kurokawa Mari. Having confirmed that the elf was in no immediate danger, Itami decided to bring her along as they retraced their steps back to Alnus by passing through Coda Village. Kurokawa takes a verbal jab at Itami, implying his motives aren't entirely altruistic, but rather he is more interested in her fantasy status, stemming from his Otaku tendencies.

The Village Chief of Coda was shocked to hear about how the elves' settlement had been burnt to the ground. The Chief becomes deathly afraid when Itami described to him the dragon. The Chief realized it had to be the Flame Dragon. Itami was wondering what had caused the villagers to be in a panic. The Chief explained that a Flame Dragon which had tasted the flesh of elves or humans would continue to attack any nearby settlements. Coda was one such settlement.