I'm not very familiar with the 'cinque gaul dog days light novel'. It might be a relatively niche or specialized work. You could try looking for it in specialized light novel communities or websites for more detailed information.
You could also try reaching out to light novel fan communities. There are many online forums and groups dedicated to light novels. Members of these communities might be able to tell you where they got their copy of the 'cinque gaul dog days light novel', or they might even be willing to share their own copy if it's allowed within the group's rules.
I'm not sure specifically what the 'invader of darkness story' is about without more context. It could be a fictional tale about a character or entity that invades a world filled with darkness, perhaps to bring light or cause chaos.
Well, 'invader visual novel' could be about a variety of things. It could center around invaders from another dimension or planet. Maybe it tells the story of a group of people who have to face these invaders. It could explore themes like survival, heroism, and the human spirit in the face of an alien or unknown invader threat. There might be different story arcs depending on the choices the player makes in the visual novel.
It depends on how you look at it. Some fans consider the comics canon because they continue and enrich the storylines from the show. However, others might have reservations based on personal interpretations.
You can start by finding a collection or anthology of Invader Zim comics. Many bookstores or online platforms sell them. Then, just open the book and start from the first page.