Kratos is incredibly powerful, but it's hard to say if he's the absolute strongest. Different fictional universes have their own mightiest characters, and it depends on various factors like their powers, skills, and the context of their stories.
The story of Kratos is complex and compelling. He was once a servant of the Greek gods but was betrayed and wronged, leading him on a violent path. As the series progresses, he grapples with his actions and tries to find a way to atone for his sins.
Kratos' height in comics varies depending on the artist's interpretation. But generally, he's depicted as quite imposing and towering over most characters.
Sorry, but Kratos is not a part of the Record of Ragnarok manga. The manga has its own unique cast of characters and plot developments that don't include Kratos.