On this page of the Assassin's Creed Valhalla tutorial, you will find a description of how to win the duel with a boss named Hemming. You will learn: when the confrontation with Hemming begins, what attacks the boss has at his disposal and how to avoid them, as well as how to defeat him quickly and effectively.
The duel with Modron happens while passing the Of Blood and Gods mission. Eivor went to Snotingham called by an old friend, Vili. As it later turned out, it's the seriously ill Jarl Hemming who called Eivor, in order to help persuade Vili to take over the leadership of the clan after Jarl's death. The hesitant Eivor is looking for help from an oracle, who is leading him into a trance. There he meets the late Hemming and has to fight him.
His estimated power is 250 points, so if you haven't reached this limit yet, the duel may be much more difficult.
During the fight's first phase, Draugr Hemming uses a two-handed spear, which makes his range of attacks very big. Draugr Hemming has three weaknesses: left forearm, right forearm, and right knee. When you hit them, the boss will be stunned, which opens him up for a very strong blow, which will thin the boss's health bar by about 1/3rd.
Most of Hemming's special attacks are indicated by a yellow rune flash - they can be blocked or evaporated. Beware, however, of the powerful blows that are indicated by the red flash of the rune - these must be avoided.
At some point, the opponent will move a little farther and start throwing lightning bolts in your direction. Jump over the rocks rising from the ground to face Hemming again. Now the Jarl will fight with two spears and his attacks will be much faster. Many cuts and thrusts will be combined into deadly combinations that can deprive Eivor of many health points.
When you have collected enough health points for the boss, the opponent will move to another area of the arena once again. In the last phase of the duel, you have to watch out not only for the fast attacks of the opponent but also for the lightning that will hit the ground all over the arena.