While Three Banner's War rages through the mainland Tamriel Solstheim remains mostly untouched by outside forces. With the recent popularisation of Stalhrim "Frostcaster" equipment, this curious resource started to attract more and more foreign looks from both trading companies and many, many treasure hunters and adventurers. It was not in Ebonheart Pact's interest to centralise the island, so it remains a semi-savage no man's land. At least for now.

Setting:

The DLC takes place in a Murkmire-sized zone - Solstheim - known from TES III: Bloodmoon and Tes V: Dragonborn. It's still long before the Septim Empire will start to dig out Stalhrim on a great scale.

Idea:

This zone uses in game day-night cycle (3 hours each)
During the day it's a PvE only zone, and during night it becomes open-PvP zone with no pre-set teams (however teaming is of course allowed by forming groups). Everyone is your enemy until the dawn. During the night pve mobs become much stronger. During the night you cannot leave the zone (mostly, look: safehouses) and if you quit your game your character stays logged in. If you die during the night you get transported to the nearest safehouse and have to pay a fine of some stalhrim coins if you want to leave it during the night.

Mechanics:

Stallhrim Coins:
They work like Tel-var stones and are lost on death as well, but they are much more valuable. It can be gained during the day by collecting resources (small drop chance from every node), and killing some bigger monsters. During the night their drop rate is much higher and they drop from all kinds of mobs, and players as well. They can be used to buy some highly-valuable things.

Safehouses:
They are two types of safehouses, the protected and the neutral.
Protected: Nothing can happen inside of them, you are always safe, there are wayshrines inside and you can leave the zone safely, entrance is free, there is one catch: once the night starts, the gates will closes and you won't be allowed to enter them no matter the circumstances (you can always leave using the wayshrine or by paying a fine of some stalhrim coins to go outside during the night)
Neutral: You can enter them even during a night by paying coins, however they are not entirely safe, during the night large groups can attempt to siege down those safehouses (not easy) to collect all the fines paid by the people who entered (everyone person in the group takes their part of them). Once destroyed they cannot be used that night again.

Freezing:
Night on Solstheim are cold, and they affect your combat abilities. Each 5/10 minutes you spend in the wild during the night your temperature (de)buff increases:

Warm: +10% to all stats
Default: +0% to all stats
Cold: -10% to all stats
Freezing: -20% to all stats

You can warm yourself again at the randomally scattered campfires, however it might be dangerous, because they can be seen from a very long distnace, especially during the night.

Potential map:

On map there are three zones based on the distance from the nearest safehouse.

Green - Protected Safehouse
Orange - Neutral Safehouse
Black - Potential Delve/Public Dungeon/Something




Please, share your opinion about this idea, I know it's quite ambitious but ZOS did many great things in the past, and they can probably do that too.