Void Knight

A Void Knight is a fighter who has attained reality warping powers, perhaps through being exposed to powerful magic, a cosmic entity or something else. 

Fighter Level	Feature
3rd	Cosmic Leap, Void Blade
7th	Reality Fold
10th	Cosmic Mastery
15th	Void Paralysis
18th	Judgement of the Void

Cosmic Leap

When you take this subclass at 3rd level you can fold the fabric of reality to leap across the battlefield. As a bonus action you can teleport up to an unoccupied space you can see with 30 ft of you. When you do this each creature within 10 feet of where you left must make a dexterity saving throw (DC = 8 + your proficiency bonus + your strength or dexterity modifier) or take 1d6 force damage and be pulled 5 feet towards the area you left. 

Void Blade

At 3rd level you can slash enemies with a blade formed from a tear in reality. Once per turn, when you take the attack action you can replace one attack with this feature. chose a point within 60 ft of you, each creature in a 5 ft cone extending from that point (facing in a direction you chose) must make a dexterity saving throw (DC = 8 + your proficiency bonus + your strength or dexterity modifier), taking 2d8 force damage on a failed save or half as much on a successful one. You can use this feature a number of times equal to your proficiency bonus times per long rest. 

Reality Fold

At 7th level you have the ability to warp the position of your enemies. once per turn, when you take the attack action you can replace on of your attacks with this feature, if you do this you cannot use Void Blade this turn or if you have already used Void Blade this turn. Make an attack roll against a creature of your choice within 60 ft of you, you can chose to use strength or dexterity for this roll. On a hit the target takes 1d8 force damage and is pulled up to 30 ft towards you. you can use this feature a number of times equal to your proficiency bonus. 

Cosmic Mastery

At 10th level your mastery over powers of the void increases. You gain the following benefits:

The range and AOE of Cosmic Leap both increase by 5 ft. 

The AOE of Void Blade increases by 5 ft. 

When you use reality fold you can pull a creature an additional 10 ft towards you. 

Void Paralysis

At 15th level you can freeze sections of reality. When you hit a creature with an effect granted by this subclass their speed is reduced to 0 until the end of their next turn.

Judgement of the Void

At 18th level you can slash through the void. As an action you can cut the fabric of reality, tearing it into millions of pieces. Each creature within a 15 foot radius sphere cantered on a point you can see within 60 ft of you must make a dexterity saving throw (DC 8 + your proficiency bonus + your strength or dexterity modifier) taking 8d12 force damage on a failed save or half as much on a successful one or half as much on a successful one.