Kobolds are not giants, and just because it's a dog-like creature, doesn't mean you should just arbitrarily change the name of the species from the raw.
Runequest trolls have snouts (reading the
Japanese Wikipedia page on trolls mentions Runequest):
Giants, Ogres, Trolls, and Cyclopes are the normal "Giant creatures" in fantasy. Sometimes also "Titans", but that's can just be another flavor of "Giants".
Kobolds are always small. Ranging from shorter than a goblin to human-sized.
It would make sense in a manga like this to take the average appearance of a "troll" and clean it up to make it more appealing to the audience you're aiming at, since the character is a female that's part of the main cast. So it doesn't seem far off to just make it dog/fox-like, since people like that shit.