So you want to play warlock huh? The delver of dark magic, the edgiest character next to the rogue.
Maybe you just really like Cthulhu and you're like,
"Yeah, uh, hmm. I'll have what he's having."
Here's how to play WARLOCK.
Warlocks are notoriously one of the most
EVIL
Classes to play in Dungeons and Dragons.
At Level One, you gain two abilities:
Otherworldly Patron and Pact Magic
Otherworldly Patron allows you to choose one of the three
(Or five if you have Xanathar's Guide)
Patrons to grant you your Voodoo Mama Juju spells
There are three to choose from:
The Archfey: a whimsical elven spirit who watches over the Feywild
She or he may grant you the curious nature of many woodland folk who derive their mystical powers from the being.
The Fiend
You choose the F***ING DEMOGORGON as your patron and wreak havoc on to the world with the game's S***TIEST abilities known to date!!!
"Alright, Jacob, it is your turn."
"All right, I'm gonna attack him!"
"CRAP!!!"
"I'm going to use my ALMIGHTY ELDRITCH DEMON POWERS AND USE MY DARK ONE'S LUCK!!!"
"yay... twenty-seven..."
"don't get that until another long rest..."
MAXIMUM OOF
The Great Old One
Basically, it's all about the mix of knowledge, power, and using it and all that.
"BUT YOU GET ALMIGHTY TENTACLE POWERS SO YOU CAN PRAISE THE MIGHTY CTHULU!!!" 



And if you're using Xanathar's Guide
The Celestial: An otherworldly angel who grants you the power of life and goodness.

wot
"Are you the Cleric?"
"Nope..."

Or the Hexblade.
"F***IN' SHOW FIGHTER THE ONE-TWO AND STAB PEOPLE WITH YOUR SWORD USING YOUR CHARISMA!"
I have trained for years in the art of combat...
This sword is an extension of myself.
I will destroy you with my fighting powers!


Pact Magic: You get to cast spells given to you by your patron.
You gain an almighty GRAND total of  
two spells.
and two cantrips with one spell slot.
Why??
Because you're a piece of garbage, that's why. 

Level Two: Eldritch Invocations.
You can choose up to two of the many invocations in the warlock class
Some of them are super awesome and can enhance your abilities as a warlock, like Agonizing Blast and Armor of Shadows
Or, you could take Eyes of the Rune Keeper and Beast Speak [sic]
"Dude, you don't want to mess with Mythogolek the Devastator."
"And why is that?"
"He has Eldritch Invocations!"
"What can he do with Invocations?" just look?
"Just look..."
"No one understands me like you do."
"THE HORROR!!!"
At Level Three, you get to pick your Boon.
There are three boons to choose from.
The first being Pact of the Tome.
Pact of the Tome gives you knowledge and understanding and new cantrips that you can cast.
Pact of the Blade: You can summon a weapon into your hands to defeat your foes
"AHHHHHHH!!!
And Pact of the Chain: You get a familiar

"I call upon the powers of the Great Old One!"

"What the hell."
Levels Four, Five, Six, Seven, Eight, and Nine are all ability score improvements and new spells along with the new invocations,
so you can slowly upgrade yourself as you level up picking different invocations and spells to improve your warlock powers.
The only new ability you'll get is Mystic Arcanum,
which allows you to cast six level spells, so warlock kind of almost feels like it falls short.
"EXCEPT FOR LEVEL 20!!!"

"AT LEVEL 20, YOU GET YOUR EPIC ABILITY KNOWN TO RIGHTFUL MORTALS!!!"
"TO DEVASTATE UNIVERSES!!! TO CONQUER UNKNOWN LANDS!!!"
You can spend a minute,
and gain all of your spell slots back once per long rest.

