The Siblings

The Siblings Patron is a more unorthodox of patrons, as instead of one singular patron, instead the unifying effects of "The Siblings" is what gives it's warlocks power. The Siblings in this context is going to be a secret society, such as cults, conspiracies and schemes. Sibling Warlocks are often trained from an early age to become champions of these secret society, often being indoctrinated into their beliefs. As such, one would usually roleplay a Sibling Warlock as narrowminded in their beliefs, as well as displaying odd behaviors, due to their lack of interaction with the outside world.  

Unity of the Siblings

At level one, you can call upon the Order to help you in your endeavors. Whenever you do a skill check or make an attack roll of any kind (applies to spells with attack rolls as well), you may telepathically call upon a more experienced member of your order to aid you, thus giving you the benefits of a help action. This ability can be used half your charisma modifier per every short or long rest.  

One of the Siblings

At level 1, you know of a secret language, it's name unknown, but it is instantly recognizable to you should you see or hear it. You can also instantly recognize other members of your order, even if they are in a disguise or have their appearance obscured. you will also know their name, even if you were never told it.

Siblings of Eternity

At 6th level, you gain the ability to call upon members of the order that are deceased. Whenever you kill a humanoid creature, you have the choice to cast a ritual upon the body, allowing for the body to be possessed by a random member of your order. The order member will share the strength, dexterity, and constitution of the host, but Intelligence and Wisdom is randomized (determined in the same way you would a player character, roll 5d6, ignore the lowest die, add up the rest), Charisma is the same as yours. Beyond that, it's abilities are the same as a Zombie (refer to Monster Manual page 316, entry Zombie). You can have up to 1 of these zombies at a time, in which it stays until it's health goes to zero. Their health is always one fourth of your health, rounding up. The zombie also share the same proficiencies as you. 

 

New Siblings

At 10th level, you can cast a more powerful version of the Friends spell. Instead of lasting for 1 minute, it lasts for 5 minutes, and instead of being friendly with you, they are undyingly loyal to you. The creature cannot have a Challenge Rating that is greater than your level, must be a living creature, and must be a medium sized humanoid. If the creature has resistance to charm effects, it has no effect. This ability can be used once per short rest. 

Siblings Share Secrets

At level 14, you are entrusted with the secrets of your order, and the power that comes with it. Once per short or long rest, you may cast a ritual that gives you temporary access to one of these abilities:

• Enlightening Secret: Pick one spellcasting class. you gain 4 level 3 spell slots in that class, and may have three spells from the appropriate spell list prepared. The spell slots increase to level 5 spell slots at lvl 17.
• Maddening Secret: You gain a number of charges equal to your charisma modifier. These charges can be used to apply the frightened condition to a creature for 4 rounds. If you run out of charges, you become frightened for 1 minute. At lvl 17, the effect will also make the target stunned for 1 round the first time it's applied to a creature.
• Powerful Secret: You gain an extra warlock spell slot, and can also cast a warlock spell without using a slot, but you go all the way down to 1 hitpoint. You can only use the second half of this option if you are at least at half your health.

You can switch these out whenever you take a long rest. They also recover after a long rest