The Tempest

Be it from exposure to the Elemental Plane of Air or having an ancestor with innate lighting powers, much like you're sorcerer cousins, you have been born with magic coursing through you. 

Unlike them, however, you were unable to manifest it externally to imitate spellcasting. Instead, you use your own body and weapons as outlets for the storm coursing within you.

 

Conduit

When you choose this archetype at 3rd level, at the start of your turn you can cause electricity to sure through you until the start of your next turn. While you are in this state, you gain the following effects:

• Your walking speed is increased by 5 feet. this bonus increases to 10 feet at 13th level.
• Your Sneak Attack damage is lightning.
• You can use Sneak Attack even if the melee weapon does not have the finesse property, however it cannot have the two handed or heavy properties. 

Aftershock

Also at 3rd level, you can redirect the electrical energy released, yet unused, by your attacks. While Conduit is active, if you make a weapon attack on your turn and do not deal Sneak Attack damage, you can use your bonus action to force the target of your last attack to make a dexterity saving throw. On a failed save the target takes lighting damage equal to your Sneak Attack damage.

Tempest Class DC

The DC for your tempest abilities is equal to 8+ Your Proficiency Bonus+ Your Wisdom Modifier

Lightening Step

When you reach 9th Level, you gain the ability to accelerate yourself to blinding speeds. If Conduit is active, you can use your bonus action to teleport to a location you can see within 30ft of you.

You then have advantage on the first melee attack you make before the end of your turn.

You can use lightening step as a reaction to using Aftershock.

Paralyzing Strike

Staring at 13th level, you learn where and how to channel your powers in order to disrupt a creature's ability to move. When you deal lightning damage with Sneak Attack or Aftershock, you can force the target to make a Constitution saving throw. On a failed save, the target is paralyzed until the start of your next turn.

You can use this feature a number of times equal to your Wisdom modifier (minimum of 1) and recover all uses when you finish a long rest.

Arcing Strike

Starting at 17th level, whenever you deal lighting damage to a single creature and not as part of an are of effect, you can have another creature within 10 feet of the target take half of that amount.