The High School DxD English novel is not really a pure - innocent read for young readers. It has scenes and storylines that are more appropriate for an older teen or young adult audience. The novel often features characters in somewhat revealing outfits and there are some flirting and romantic relationships that are a bit more grown - up in nature. So, parents should be cautious if considering it for younger kids.
It depends. While the High School DxD English novel has some elements that might be appealing to young readers such as the high school setting and some adventure elements, it also contains some mature themes like fan service and some sexual innuendos. So, it may not be entirely suitable for very young or immature readers.