Well, 'seikai no monshou light novel' could potentially revolve around a hero's journey. Maybe it has a protagonist who has to face various challenges in a fantastical realm. It might also explore themes such as friendship, loyalty, and the struggle between good and evil. The light novel format usually allows for in - depth character development and a richly detailed world - building, so it could be full of interesting sub - plots and unique cultures within its fictional universe.
Since I haven't read the 'seikai no monshou light novel', I can't name the main characters. However, in most light novels, the main characters are often the ones driving the story forward. They could be a young hero or heroine with special abilities or a strong will. There might also be a group of supporting characters who play important roles in the main characters' development and in the overall plot.
Well, 'Sword Art Online' might be of interest. It has an engaging plot and a lot of action, much like 'seikai no senki light novel' in terms of the exciting adventure aspect. There's also 'Re:Zero − Starting Life in Another World' which has a unique take on the isekai genre.