86 is indeed a light novel. It gained popularity as such and then branched out into manga. The light novel typically offers more detailed character development and in-depth exploration of the story's themes compared to the manga adaptation.
Radiant is primarily a manga. It features detailed illustrations and a captivating plot that has attracted a wide audience. The manga version has a dedicated fan base.
No, they're not the same. Light novels have more text and focus on storytelling through prose, while manga is a visual medium with pictures and speech bubbles.
Monogatari started as a light novel. The success of the light novels led to manga adaptations and other media expansions. But its roots are in the light novel format.
Light novels and manga have some differences. Light novels often focus on detailed descriptions and inner thoughts of characters through text. Manga, on the other hand, conveys the story mainly through images and has a more visual impact.