Stormdark Mage

Warning!  This is a broken subclass. Use at your own risk, and feel free to give advice on how to balance in the comments. Also, I didn't write the flavor text below, the other person that was working with me did.

Stormdark Mages usually have a rough, emotional childhood and tend to be moody, often taking things to the extremes. They have all of the features of a rogue, but, when the player chooses, the rogue discovers their Giant Ancestry and becomes a Stormdark Mage. Stormdark Mages are extremely rare and not very widely known, except the fact that they can be dangerous. They are almost like the alter ego of most giants and are basically a mashup of Sorcerers, Rogues, and Druids. They are based off of the Rogue class and have all of the Rogue features as well as Stormdark Mage features.

Giant Ancestry

Your ancestor is a Storm Giant. When you cast a spell that does Thunder or Lighting damage, add +2 to that damage.

Enhanced Shout

 Your voice permanently has the effects of the Thaumaturgy cantrip, but only the booming voice part. It would be like going from talking to singing. When you shout too loud, your voice switches to the enhanced shout. You also learn the Thaumaturgy cantrip.

Giant Understanding

You are fluent in Giant.

Giant

You are fluent in Giant

Giant Familiar

You befriend a tiny or small creature themed around your ancestor -- usually a dangerous one -- and it becomes your familiar. You can’t summon it; it has to show up in person. It is up to your DM's discretion the creature that you befriend.

Giant Strength

You have learned to fully tap into the strength of your giant heritage. As an action, you can have you're strength score become 19 for 1 minute. (+10 for attacks made with STR weapons (anything without finesse), unarmed strikes do 5 damage unless they already do more, etc.)

You can only use this ability once per long rest.

Spellcasting

You start to tap into the magical nature of your Storm Giant ancestor.

 

Storm Connection

You gain 5 temporary hit points during any kind of storm.