With a rather satiric message that points to the innate enjoyment of the children for the gruesome rather than the uplifting, Saki's ironies further the thematic development of "The Storyteller." That the young bachelor, who has no experience with children and less with life than the prim, proper aunt, is able to intrigue the children with his "improper story" is ironic of itself. And, that innocent children should delight in the bachelor's oxymoronic introduction of the protagonist of the his story as "horribly good" and that they are not frightened by the description of the "enormous wolf" who comes to eat the pig, instead asking, "What colour was it?" is also ironic.  

Likewise, the rather gruesome details of the wolf with his

black tongue lolling out of its mouth and its pale grey eyes glaring with rage

 do not disturb the children at all; instead, they become absorbed in the tale.  And, ironically, when the bachelor concludes his narrative by telling the children that the wolf killed the good girl because he heard her medals for good conduct, the children merely ask, "Were any of the little pigs killed?" indicating that they are completely unconcerned that the girl has been eaten or that she has been killed because of her goodness. Then, the "smaller of the small girls" remarks that the tale "was the most beautiful story that I ever heard" they truly concur that the girl was "horribly good" and the reader understands the full irony of this phrase as well as the theme that what in morally instructive is not always interesting.