Added 13 minutes later
And also... Sigrun's specialization states: Reduces the speed of enemy creatures of the hero. The higher the hero's level, the stronger the effect [hero's level/10, rounded up], etc., reducing movement points.
I didn't notice this effect at all at hero level 19. Either I'm misunderstanding something, or what? The speed of all enemy units in battle remains the same. For example, there's some enemy Dwarf. He has Erlings. Outside of battle with Sigrun, their speed is 8, and in battle with Sigrun, their speed is also 8. Although, logically, 19/10 rounded up equals 2, and 8-2 = 6.