How is Dark Messiah connected to Heroes of Might and Magic?

Agrail was obeyed only because of his talent and fear of Beleth; essentially, Agrail simply earned a reputation when they were choosing the Master's right hand, and he did so, I must say, not without Biara's help. As for Ksana's devoted love, she was simply trying to sway Sareth to her side and could not possibly love him if he freed her father, because she understood that she would be doomed to torment in Sheogh, and her character is very similar, at least in terms of cynicism, and I wouldn't say that Biara is tougher than Ksana, except that she is more loyal to the Master, and that's it. I've already talked about the appearance; Kha-Beleth, for example, looks drastically different in Heroes of Might and Magic V: a different helmet, armor, no cloak or sword, darker colors; all of this, even considering the cartoonish style of Heroes of Might and Magic V, are quite significant differences in appearance.

Linna cannot be the daughter of Raelag and Isabelle because she is the last of the Falcon clan.