Domain Expansion - Valhalla's Storm & Fury

Starting at level 4, once per long rest you can create an extradimensional pocket of space which you immediately teleport yourself and a number of creatures to. The number and CR of the creatures that come with you is determined by the dm. The pocket dimension is a 60ft by 60ft space, in a terrain and design of your choosing. You and any creatures brought with you, reside in this space for a duration of 3 rounds. Once this has been created, when the domain ends, you fall unconscious with exhaustion. You are essentially stunned and prone for one round. Additionally you suffer 3 levels of exhaustion and half of your spell slots are expended. Unless someone spends a portion of their turn waking you, you remain unconscious. You can end the domain before the 3 rounds are up by using a bonus action to dismiss it. The effects on you still occur. 

While inside the realms barriers, others who wish to leave must use their action to make a Wisdom save against your DC at disadvantage if you don't want them to leave. Anyone outside the realms barriers that wishes to break in must use their action to make a DC 20 strength save. The realm does not shatter but the hole remains for 1 round until the barrier can heal itself, allowing an exit or entrance for other creatures. 

Your domain will be treated like a Lair and thus will have lair actions. Your Domain/Lair will have an automatic initiative of 20 (losing any ties) and can do 1 of the following: 

• Odin's Foresight. Until the end of your lairs next turn you and all of your allies within the space have advantage on any attacks and saving throws. Any attacks or saving throws made by any creature against you or your allies within the space are done so at disadvantage. 
• Lightning Storm: The storm above rages further and creates three bolts of lightning, each of which can strike a target you can see within 120 feet of it. A target must make a Dexterity saving throw against your spell DC, taking 22 (4d10) lightning damage on a failed save, or half as much damage on a successful one
• The Valkyries Call. A loud horn sounds throughout the domain followed by the sound of many hooves as Valkyries race across the domain astride their pegasi. Any hostile creature within the space must make a Dexterity saving throw against your spell DC. Taking 22 (4d10) bludgeoning damage on a failed save and be knocked prone, or half as much on a successful one. 

Starting at 10th Level you are the master of this domain and thus have Legendary Actions you can use at the end of each creatures turn. You may use a total of 3 actions per round: 

•  Loki's Tricks. You can make 1d4 illusions of yourself appear evenly distributed around your domain; you can cast your spells through any illusion. If any of your illusions are targeted, on a hit you can roll a d4 to see if it hits the real you or an illusion. (1 Action)
• Thor's Rage. You cast Chain Lightning (resets on a 5-6 d6 roll). You create a bolt of lightning that arcs toward a target of your choice that you can see within range. Three bolts then leap from that target to as many as three other targets, each of which must be within 30 feet of the first target. A target can be a creature or an object and can be targeted by only one of the bolts. A target must make a Dexterity saving throw. The target takes 10d8 lightning damage on a failed save, or half as much damage on a successful one. (3 Actions)
• Freya's Fury. You cast Destructive Wave. You strike the ground, creating a burst of divine energy that ripples outward from you. Each creature you choose within 30 feet of you must succeed on a Constitution saving throw or take 5d6 thunder damage, as well as 5d6 radiant or necrotic damage (your choice), and be knocked prone. A creature that succeeds on its saving throw takes half as much damage and isn’t knocked prone. (2 Actions)
• Stormbreaker. You call the storm to your aid and harness its power within your blade. Your weapon is sheathed with crackling energy. Your next melee attack deals an additional 3d8 lightning damage. Any target you hit must roll a strength save against your spell DC or be knocked 20ft back and fall prone. (1 Action)
• Yggdrasil's Blessing. A wave of healing energy washes out from a point of your choice within 30ft of you. Choose up to six creatures in a 30-foot-radius sphere centered on that point. Each target regains hit points equal to 4d8 + your spellcasting ability modifier. This spell has no effect on undead or constructs. (1 Action)