In your opinion, which hero has the most charisma in the campaign?

Isabelle probably forgot that Markel killed Nicholas's mother.

You're mistaken...
He was her advisor, and when she died (of natural causes), he was exiled from the Griffin Empire.

No, he was like that from the beginning.

Read the biographies of the "old" Laslo and the "new" one.

I'll give you a rough idea about the new one:

Laslo used to be a loyal captain in the Griffin Empire's army, but Biara corrupted his thirst for glory over several years, turning his love of battles into a thirst for blood, and his search for recognition into a desire to be recognized by her and only her.
Biara now completely controls his desires...
Demanding and cruel, he even looks at his own soldiers as food for vultures...

The description of the old Laslo is completely different... (he's just strict and respected, without a thirst for blood, but seeking GENERAL recognition).

But without Isabelle and Agrael, the world would be a hundred times better.

Without Hitler and the USA, the world would be a million times better too...
But without Isabelle and Agrael, there wouldn't be a worthy plot...