Well, for some values of light… starting from it’s origins as a web novel, there are over 280 chapters, running 4,000 – 5,000 words each. At well north of a million words (even without the side-stories), it’s about 4 western-length novels or 1.5 Robert Jordan novels. It is also complete, although there’s room for sequels, and the author is still writing side-stories in the main canon.
I will take a bit getting into the setting, because I want to be clear: it’s the best of the Japanese LN’s that I’ve ever read. It’s close enough to the usual tropes and events to be accessible, but it does not lend itself to being the 5000th iteration of any of them. Probably the strongest trope is that the protagonist is genre savvy, and his internal monologue is full of anime references. Many other tropes appear, but they’re not substituted for story; there’s no feeling that the author was going down the list, mumbling “meet-cute, check; child-hood friend, check; face-heel turn, check….”
Moreover, it’s an unpredictable story, with arcs that last multiple volumes. People enter the story, leave for several volumes, and then come back naturally. Sometimes they’ve changed, sometimes they haven’t. Things which happen may not be explained right away, or have unexpected consequences years later. Through the twenty-plus years covered by the story, there are probably only two such contrived incidences; only one really doesn’t make sense. Which for LN’s of this pedigree and length, is damned amazing, IMHO.
So what is it about? Swords, sorcery, and a transplanted hikkimori:
A 34-year-old NEET otaku was chased out from his house by his family. This virgin, plump, unattractive, and penniless nice guy found that his life was heading towards a dead end. He recalled that his life could actually become much better if he can get over the dark history of his life.
Just when he was at the point of regret, he saw a truck moving at a high speed with 3 high school students in its path. Mustering all his strength, he saves them but ended up getting run over by the truck, which kills him.
The next time he opens his eyes, he had reincarnated to a world of swords and magic, as Rudeus Greyrat. Born to a new world and a new life, Rudeus declared, “This time, I’ll really live my life to the fullest with no regrets!” Thus begins the journey of a newly made man.
This glosses over a lot. I’ll be blunt: his siblings chased him out, not because they’re assholes, but because he was anything but a nice guy. In fact, while they’re attending their parents’ funeral, he’s sitting at home fapping to an AV. Small wonder his brother took a baseball bat to his laptop… and him.