Overlord is actually both. The light novel provided the foundation and the manga was created based on it. While they share the core concepts and characters, there can be differences in the presentation and emphasis in each medium.
The main difference lies in the art style. The manga has visual representations which can enhance the understanding of the story's settings and characters. For example, the unique designs of the various races in the Overlord world are more vividly shown in the manga. While the light novel goes more in - depth with the descriptions and inner thoughts of the characters, allowing readers to have a more detailed exploration of the story's plot and character development.
It's hard to say which one is more popular. The light novel has a large following among those who enjoy in - depth storytelling and detailed world - building. They like to read the long descriptions and explore the complex characters through the written word. However, the manga has also attracted a significant number of fans, especially those who are more visually oriented. They are drawn to the beautiful art and the more immediate visual impact of the story.
In most cases, the Overlord light novel is ahead. It provides a more extensive and in-depth exploration of the story. The manga, while visually appealing, has limitations in terms of the number of pages and the speed at which it can cover the narrative.
I don't have the exact answer for that. It could be related to a specific manga series, but you might have to do some research on manga databases or ask in manga enthusiast communities to get a definite answer.
You might find it mentioned or referenced in the supplementary materials or special editions of the light novel. Sometimes, there could be notes or appendices that point to where the manga is included.
Another one could be 'Sword Art Online'. Although it has some differences, it shares the idea of a virtual world where the characters have to fight and survive. It also has a strong lead character like 'Overlord'.
Volume 15 of 'Overlord' light novel likely delves deeper into the power dynamics in the story. Ainz's unique form of leadership and his attempts to assert dominance while also maintaining some semblance of order are probably explored further. The magic system in the world of 'Overlord' may also be expounded upon, with new spells or magical artifacts being introduced that could change the balance of power among the different factions in the story.
The Overlord light novel has indeed come to an end. All the main story arcs have been wrapped up and it provided a satisfying conclusion for the readers.