It has been ten years since the Battle of the Five Armies. It was a huge loss for Sauron, the Dark Lord has not given up. Now the Dark Lord will seek to build up ties with allies and start a new age of darkness.
Sauron contacted the Witch King at the Witch King's fortress of Minas Morgul via Palantir.
"What is it my master?" asked the Witch King.
Sauron said "The mission to take over the dwarven lands of Erebor has been a failure. When the free people unite, they truly can be dangerous to our cause, which is why we need to increase the influence with our allies, and have an ideal counter to the free people."
The Witch King asked "Where can we start?"
Sauron said "North Barrow Downs is ruled by a very loose leader as you know."
The Witch King said "I know. Laurtuen is not very reliable at staying on our side."
"Precisely why we must have a change of rulership. Your ties to North Barrow Downs are excellent, for it is you who have helped the Barrow Wights obtain their lands." said Sauron.
The Witch King asked "So you want me to go to North Barrow Downs, and slay Lartuen?"
"No" said Sauron. "I want the free people to suspect nothing. If you intervene directly, do not be surprised for them to call out for an invasion of North Barrow Downs. However, Lartuen's popularity is very low. So, what we need is a new leader, one that will do our bidding."
The Witch King asked "What do you want me to do my lord?"
Sauron said "I need you to contact his aid, Dorwen. Lartuen may be against us, but not everyone in Lartuen's group is loyal to him. What we need is for Dorwen to know that we need an excellent battalion, and our training can begin. Many new trainees should be joining this year and North Barrow Downs is the only ally we have in the region, to lose it means an entire region where we have no influence."
"I like this plan. We will crush Lartuen from the inside." said the Witch King.
Sauron proceeded to contact Dorwen via Palantir. A blazing reddish-orange reptilian eye popped showed up in a dull orb right in front an average height, skeletal figure.
Dorwen asked "What is it my master?"
Sauron said "I proceed Lartuen is still staying 'neutral'."
Dorwen said with a sigh "Unfortunately, yes. He does not seem to be budging. What is the plan?"
Sauron said "Lartuen's neutrality is a compromise to my planned alliance, and we will need new management to get the plan through. Which is why you will get an excellent military battalion and send them to Minas Morgul. To avoid suspicions, you will tell them this is special training sessions, ordered by Lartuen himself."
Dorwen said "I understand where this is going. Don't you think the free peoples will suspect our involvement and launch an invasion of North Barrow Downs."
Sauron replied with "This plan is to intentionally prevent such thing. Lartuen is already unpopular with most Barrow Wights and with making it look like the military was also angry. We take him out without any direct external involvement which means it will cause an avoidance of an offensive attack by the free people."
Dorwen said "It will be done."
The eye disappeared from the Palantir.