yeah sure its a japanese mmo, with an open setting, not hasving katanas or skills for that. who would believe that
Not the smartest author behind this story. Besides, they do have katanas. An earlier chapter said nobody has acquired a katana skill despite having the weapons themselves. In this chapter the fox girl is carrying a katana. Not to mention, in a past chapter Crim got an axe skill by chopping wood with an axe. So, you most certainly should get a katana skill by fighting some goblins or whatever with a katana. Maybe some special katana moves could be unlocked via quests, who knows, but the story has specifically said that nobody managed to unlock the general katana skill. Though I don't know why you'd need a specific katana skill. It's just a slightly curved long sword. Anyone who can use a sword can use a katana.
I guess all of this is because of the glorious hundred thousand times folded nippon steel. Never seen that trope before in manga, haha.