The unnatural bond of the Oblex is one that very few find worth it's potentially horrific costs. however, it is not impossible to find some form of alliance with one. they are a creature that seeks neither good nor evil. only to survive, become stronger, and add to its powerful network of Spawn.

if one is to bond willingly to an Oblex, they gain powerful abilities, but at the cost of the life energy an Oblex requires to survive.

You gain the following benefits.

• You can cast the Spell detect thoughts at will
• you can sense the mental presence and general location of invisible creatures as long as their thoughts are not shielded by other means.
• you are immune to being charmed or mind-controlled by any means.
• Your intelligence score becomes 19

You can Cast any of the following spells, which for you can be cast up to 5th level. however, using these spells does not take Spellpoints, but rather is fueled by your life energy. when you use a spell with the Oblex Soul, you must a DC 15 Constitution saving throw. on a success, you take 1d10 necrotic damage (halved) for each spell level. on a failure, the full amount is taken and deducted from your Hitpoint maximum. if your hit point maximum falls to Zero in this way, your body will be consumed by the Oblex and used as the new nucleus of the Oblex.

1st level

Cause Fear 
Charm Person
Command
Compelled Duel

2
Hold person
flock of familiars

3
Fear
Counterspell
enemies abound

4
Charm Monster
Greater invisibility

5
Circle of Power
Dominate Person
Dense Macabre (no material component or bones needed)
Ennervation

If The Oblex finds a host it wishes to move to, you can either allow the Oblex to separate from your body, leaving you with 1 level of exhaustion, or you may fight against these effects with the knowledge the Oblex will fight back accordingly.

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Legendary Action: Macabre  Simulacrum
As a Legendary action, you may sacrifice half of your life point total in to cause the Oblex to spawn as an false copy of yourself. this copy rolls its own initiative, has all of your current abilities, and has half of your current Hitpoint total before this effect.  this form lasts for 1 minute and can be refused to your body, restoring your Hitpoint maximum and gaining any hitpoints the creature has left. however,  if the Simmilacrum dies, The Oblex will die with it, leaving your Hitpoint Maximum depleted until you can finish a long rest.

 ***************while the Oblex is attached to your body, all healing effects applied to you are cut in half.

Notes: THe bonding, willing or unwiling of an unpaired Oblex