Huh, he's portrayed a lot...more of a jerk than the WN version
In the WN, Dorsen was shown to be confused over the reaction of his parents (his mom especially, who said she's on Iris side in this)
Then the army/royal guard had a sort of 5 v 5 exhibition match, in 1 v 1 format where winner stay, to fight the next person.
When it came down to Dorsen vs the last person on the other team, Gramp turned it into 2 v 2 of his students vs the not-students.
Dorsen still got rekt'd, but rather than being mad, he was astonished by their strengths and had questions on why the two didn't join either the army or the royal guards.
And they said they had a master they swore to.
Dorsen later learn from his sempai that said master is Iris, increasing his confusion even more.
i.e. the WN Dorsen were a lot more sympathetic.