Pact of the elder oblex

Oblex’s are terrifying and insane creatures. Originally regular oozes that were experimented on by mind flayers, they now have the psychic ability to drain a creature of their memories. Their own minds are blends of those they have consumed. This means they have the combined intelligence of thousands but their psyche’s are a mess of personalities mushed together. They have the power to create clones of people they have consumed. These clones act as extensions of the oblex’s will but the catch is they have to stay connected to the oblex by a string of slime. So when an aspiring warlock offers to make a pact with an oblex and become a servant that can go as far away from the oblex as they need, oblex’s are inclined to oblige. There are more reasons to become the thrall of an insane psychic goo hive mind than you’d think. Maybe you begged an oblex to set free the mind of a loved one and you now must serve the oblex in return. Maybe you were about to be assimilated into the oblex but Offer to Serve it willingly instead. Maybe you seek knowledge that the oblex has gained from someone’s memories, and the oblex has agreed to give it to you on the condition that you must become it’s servant. Or in a rather tragic case, maybe a loved one or respected superior was assimilated into the oblex and you still feel loyalty to them even if they are part of an insane goopy hive mind. Regardless of the reason, instead of absorbing your memories the elder oblex melds part of itself with you allowing you to be psychically connected to it. This allows you to fuel your magic with psychic power, as well as learning strange forms of magic from the various personalities that are part of the oblex. You will likely have to trick other creatures into becoming part of the oblex. Or perhaps you will have to perform other duties specific to certain personalities, like take revenge on behalf of an assimilated personality. The goals of an oblex can be strange and unfathomable but whatever they are you must complete them, all the while hearing the maddening voices of a thousand personalities inside your head, So good luck with that.

Expanded Spell List

The Elder oblex lets you choose from an expanded list of spells when you learn a warlock spell. The following spells are added to the warlock spell list for you. (Notes: the spells black tentacles, grease, and web are all made out of the goopy substance your patron infused into you. Also stinking cloud smells exactly like the clones created by an oblex.)

1st. Charm person, grease 
2nd. Detect thoughts, web
3rd. Hypnotic patern, stinking cloud 
4th. Dimension door, black tentacles 
5th. Dominate person, telekinesis 

Slime servant

Starting at first level you gain the ability to summon an oblex spawn. this oblex spawn  is one of the many personalities of the oblex’s hivemind, which has been put inside of a glob of the oblex slime put inside your mind by your patron. As an action, you cause the oblex spawn to appear in an unoccupied space within 5ft of you. It's friendly to you and your companions and can speak telepathically with anyone within 30ft of it. it obeys your commands but does things on its own as well, acting like the personality used to create it, you can choose a specific personality from the hivemind if you want to. In combat, the oblex spawn shares your initiative count, but it takes its turn immediately after yours. It can move on its own, but the only action it takes on its turn is the Dodge action, unless you take a bonus action on your turn to command it to take another action. That action can be one in its stat block or some other action. If you are incapacitated, the oblex spawn can take any action of its choice, not just Dodge. The oblex spawn dissolved after 30 minutes. You can dismiss it intentionally as a bonus action, if you do so a small piece of the oblex spawns memory is passed on to you. choose one intelligence or wisdom based skill and gain advantage on the roll the next time you use that skill. At first level you can summon 2 oblex spawns per day. This increases to 3 at level 6, 4 at level 10, 5 at level 14, and 10 at level 20. 

Slime sanctum

At 6th level you can, once per day as an action, surround yourself with slime to enhance your psychic powers. While in this state you are deff and blind, are immune to psychic damage and have advantage on saving throws against any mind probing effects (i.e. most enchantment spells or spells like detect thoughts, dream ect). Also while in this state you can speak telepathically to anyone you know the general position of as long as they are within a mile of you, the target can respond to your telepathy if you let them. Additionally, once per usage of this feature you can choose one person you know the general position of who is within a mile of you to attempt to infiltrate their mind. The target must make a wisdom (insight)  check contested with your charisma (deception) check. if you fail you are unable to use this feature on that creature and the creature becomes aware you tried to invade their mind, you can attempt to use this feature on a different creature but you cant try using it on that creature until you finish a long rest. If you succeed, you can choose to do one of the following things. 

1. start looking through the creatures eyes and hearing through their ears for a total of 5 minutes 
2. read the creatures base thoughts for a total of 5 minutes 
3. gain one piece of information from the creatures memories, you can ask for a specific piece of information or learn an important piece of information decided by the dm, if the creature doesn’t have the information you asked for you instead learn information decided by the dm
4. plant an idea in the creatures mind, as long as the dm thinks it’s a reasonable conclusion for the the creature to come to

 

Simulacrum

At 10th level your oblex spawn servants can take on the appearance of a humanoid that has either been assimilated by your patron or that you have used your slime sanctum to invade the mind of. The oblex gains all of your languages, and uses your charisma score in place of its own, the dc for checks to determine that the creature is not what it is pretending to be is equal to your spell save dc. You can telepathically communicate with the oblex as long as you’re both on the same plane. You can use a bonus action to start seeing and hearing through the oblex’s eyes and ears, or return to seeing through your own senses as a free action. Additionally, you can cast spells originating from the oblex spawn. 

Assimilation

At 14th level you gain the ability to tear a person’s consciousness from their body and assimilate them into your patron’s hivemind. As an action you or one of your oblex spawn servents place their hand/pseudopod on the head of a creature with in int score of 7 or higher and siphon the psionic energy from their brain. The creature must make a charisma saving throw or take 8d8 psychic damage or half as much on a success. If this attack reduces the target to zero hit points it instantly dies and you learn any information you want that the creature knows. The creatures consciousness is stored within your mind, occasionally whispering things to you inside your mind. The next time you take a rest or use your slime sanctum you can deposit the consciousness’s you have stored to your patron. You gain one bonus hp for each consciousness you deposit, if you deposit 10 consciousness’s or more you can choose to trade 10 of the bonus hp you would have gained for one bonus 4th level spell slot. You can do this a number of times equal to your charisma modifier.