Let morkvarg go, will I encounter him again

So I am this quest and have killed Morkvarg, but it leaves me curious, what if I had just let him go.

I tried looking around, but all I can find are people who just found him such a scumbag that after gathering the reward they backstabbed him to death.

But now I'm curious, has anyone ever let him roam free? Does he have an effect on npc stories? Will he become a big looting pillaging presence in the game? or does he vanish into nothingness after the quest?

So what happens to Morkvarg if you let him go into the world? Prefably answers from experience of letting Morkvarg roaming free, as the wiki's don't detail about what happens after the quest in the rare case you let him go.