"Berserk," "Vagabond," and "Vinland Saga" are often considered the seinen Big 3 manga due to their immense popularity and influence within the genre. Each of these series offers a unique blend of captivating storytelling, intricate character development, and stunning artwork that has captivated audiences worldwide. 

Berserk:
Kentaro Miura's "Berserk" is a dark fantasy manga that follows the journey of Guts, a lone mercenary with a tragic past, as he battles against demons, both internal and external. Set in a medieval-inspired world filled with political intrigue and supernatural horrors, "Berserk" explores themes of revenge, betrayal, and the struggle for redemption.

One of the defining aspects of "Berserk" is its visceral and detailed artwork, particularly during its intense and brutal battle sequences. Miura's meticulous attention to detail brings the world of "Berserk" to life, from its towering castles to its grotesque monsters.

The character development in "Berserk" is also exceptional, with Guts undergoing significant growth and evolution as he confronts his inner demons and grapples with the consequences of his actions. The supporting cast, including the enigmatic Griffith and the fierce warrior Casca, adds depth and complexity to the narrative.

Vagabond:
Created by Takehiko Inoue, "Vagabond" is a historical manga inspired by the life of Miyamoto Musashi, one of Japan's most legendary swordsmen. Set during the tumultuous Sengoku period, "Vagabond" chronicles Musashi's journey of self-discovery as he seeks to master the way of the sword and find meaning in a world consumed by conflict.

Inoue's artwork in "Vagabond" is breathtaking, with dynamic action scenes and stunning landscapes that capture the beauty and brutality of feudal Japan. The attention to detail in the depiction of swordplay and martial arts is particularly impressive, showcasing Inoue's dedication to authenticity.

The character of Musashi undergoes profound growth throughout the series, transitioning from a reckless and brash youth to a wise and enlightened warrior. Along the way, he encounters a diverse cast of characters, each with their own struggles and motivations, adding depth and richness to the narrative.

Vinland Saga:
Makoto Yukimura's "Vinland Saga" is a historical epic that blends Viking lore with elements of adventure and drama. The story follows Thorfinn, a young warrior seeking revenge against the man who killed his father, as he becomes embroiled in the conflicts of the Viking Age and discovers the true meaning of honor and redemption.

Yukimura's artwork in "Vinland Saga" is masterful, with detailed character designs and sweeping landscapes that evoke the rugged beauty of medieval Scandinavia. The battle scenes are intense and visceral, showcasing the brutality of Viking warfare while also exploring the human cost of violence.

One of the strengths of "Vinland Saga" lies in its complex and morally ambiguous characters, from the stoic and tormented Thorfinn to the charismatic and enigmatic Askeladd. The series delves deep into themes of loyalty, betrayal, and the nature of power, offering a nuanced portrayal of the Viking world.

In conclusion, "Berserk," "Vagabond," and "Vinland Saga" are three seminal works in the seinen manga genre, each offering a unique and compelling take on themes of struggle, redemption, and the human condition. With their rich storytelling, stunning artwork, and memorable characters, these manga have left an indelible mark on readers and continue to be celebrated as classics of the medium.