Instinct:

Thieves steal money, gems, lives, and art. Stealers steal secrets, souls, sights, sounds, and speech as well as money, gems, lives, and art. They were thieves once, but lost their souls and with it their consciences,turning them into monsters that only wanted one thing: everything. They only knew theft, only felt greed, and only loved loot. They often fight with their old thieves' guild. Instinct: to steal

• Steal a prized possession
• Lie their way into what they want
• If the target is weak enough, steal their soul

A master monster's monster mount. You can't escape, not easily, from a herd of them: but they are never without a master, typically a litch or necromancer. Does this even count as undead? Someone definitely reanimated it... Instinct: to serve its master

• Carry travelers to its master's lair
• Mislead travelers

Instinct:

lost and misunderstood - among humans, elves, halflings, and dwarves, - an otherworlder tries to find its way home. - pain. understanding. - the otherworld - so close yet so far - please understand. Good yet a monster, Don't kill it. Instinct: To enlighten people

• Drive others to madness unintentionally
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• Try to help people understand

Sariel had finally arrived at the top of Ramas's tower, unaware of its secret. At the top, instead of finding Ramas, she found an empty room reeking of blood. Sariel ran her fingers along a crystal and suddenly, the chair she was sitting on began to devour her. A tapestry smirked. Two watchful eyes stared into her soul. Sariel's neck was finally snapped by a statue of an owlbear, and if that's not what killed her, the mouth that opened under the floor to give her the end did. The end, but not the release. Her screams echoed through the decoy tower as she was forced to watch her sister Birel slowly approach her doom. Luckily, Birel killed Ramas in the real tower and finally slayed the Shadow Room holding so many dead bodies. She was heartbroken when Sariel's body was one of them. Instinct: to consume

• Trap others inside
• Look like a normal room to lure others inside

it mostly and pretty much always kills its prey Instinct: it wants to kill

• shape shifting
• turns you into one of them

Instinct: To sacrifice or convert to their religion

• Spread their doctrine
• Unleash Blood Magic
• They fight in an organised well trained group

Instinct: to Destroy what I cannot have

• Channel the beastmen's anger
• Create illusions to confuse the enemy
• Produce a lance-shaped missile of Deathfire
• Stay behind his minions
• Absorb the life essence of a creature to regain 8 health

A massive pile of flesh the size of a small barn stands before you. The body of a hairy man with the head of a bull and big black hooves, wearing what seems to be tatters of leather armor and wielding a massive wicked-looking Axe. Its eyes are the colour of staring into the Void, its arms the thickness of massive tree trunks. Its hooves shake the ground as it walks, its breath is like the wind, and its deafening call chills even the toughest soldier to the bone.
Its size and strength makes it extremely physically intimidating, but the hollow voids that are its eyes are what makes it truly terrifying. Most of the business end of its Axe, its Right Arm and its face plus horns seem to be blackened and burnt, with cracks of purple, glowing magic flowing through like tiny branching rivers of purple lava, which softly glow, illuminating its face in the dark.
Instinct: to Destroy Everything

• Eviscerate the enemy with wide, sweeping axe strikes, infused with dark magic
• Charge the opposition at extreme speed
• Breathe Deathfire in a cone forwards
• Knock human-sized enemies around like they are nothing
• Absorb the life essence of a creature to regain 8 health
• Proudly display a kill, sending nearby beastmen into a blood-rage
• Revel in carnage, destruction or blood