Find the Thalmor Assassin

Walkthrough
If Malborn survives the escape from the Thalmor Embassy during the quest Diplomatic Immunity, he can then be found at the New Gnisis Cornerclub in Windhelm. If the Dragonborn speaks with him, the elf sarcastically thanks the Dragonborn for leaving him in a lurch, which is to say unemployed, trapped in Windhelm and being hunted by Thalmor assassins.

Find the Thalmor assassin
The Dragonborn can then offer to take care of the assassin stalking Malborn. This assassin is just outside the city gates and his position is marked after accepting the quest.

There is a small camp just east of the Windhelm Stables, where the assassin J'datharr can be found. He has J'datharr's Note on his body that proves he is hunting down Malborn.

Tell Malborn the assassin is dead
Return to Malborn with the news, receive a reward.

Finde den Assassinen der Thalmor