Terithran
"80 Minute Alien" © Roman Sachnow, accessed at his ArtStation here
[The terithran is another monster from the original Fiend Folio all but forgotten today, and I suspect that's due to how mechanically complicated it is. It's yet another monster that abducts people across planar boundaries, and it has different abilities whether it's in the Material or Ethereal Planes. It also serves the role of a "gotcha" monster, a way to punish players for doing things the DM is annoyed with, which is not uncommon for 1e monsters. But it doesn't even really hit that mark either. Its attention is attracted by high level spells, like 7th-9th level, but it only has 5 Hit Dice! 5 HD went a lot further in 1e AD&D than it does in a modern game, but it still seems like its ire is raised only by things punching waaaay above its weight class.
To sum up, the original terithran has a lot of problems, and my conversion ran into plenty of issues when I was trying to make it actually fun and playable for PF1e. So why did I bother? Mostly because a monster motivated by delusional spite is a fun idea, and I like the image of a little creep who hates wizards.
I, on the other hand, am motivated by a love of monsters and creative energy. If you'd like to help keep that going while keeping a roof over my head, please support me at the Creature Codex Patreon here]
Terithran CR 5 NE Aberration This short humanoid thing has a swollen head with no discernible neck, and its body is glistening and covered in low ridges. Its arms are abnormally long and spindly, capable of touching the ground without bending over, and end in clawed hands.
Terithrans are bitter hermits with occult powers and a hatred for arcane magic. They universally believe that arcane magic has permanent, harmful consequences to the fabric of the planes, and do their part to “correct” this by killing magic users. Of course, as terithrans are relatively weak and cowardly, they strike out predominately at mortal wizards, witches, and sorcerers while they are still fairly frail and inexperienced. Stronger monsters that use arcane magic, such as dragons, are creatures to be avoided, but the terithran will still hold a grudge against them regardless.
A terithran spends most of its life inside its own personal demiplane, where they plot, scheme and twist themselves into knots about how much they hate arcane magic. This demiplane has porous boundaries to the terithran’s senses, and it can detect spells being cast nearby its entrance on the Material Plane. They ignore divine magic, but arcane magic cast nearby their demiplane raises their ire. The terithran then attacks from ambush, popping out of its demiplane and attempting to stun its enemies with a synaptic pulse. They focus their attacks on arcane casters, hoping to grab them and drag them back into their demiplane to kill. Terithrans will also retreat to their plane if injured or if their assault is unsuccessful, trusting to the planar boundary to protect them. If their foes manage to breach their defenses and pursue them into their lair, however, the cornered terithran often fights to the death.
A terithran’s demiplane lair is cramped and filthy, as the creatures collect all manner of items from their environments, especially those with magical auras. Terithrans see no hypocrisy in using magic items themselves, and may have stolen wands, scrolls and potions that they turn against their foes. Terithrans often vent their spleen through writing, and reams of paper can be found in their lair, occasionally with useful insights into the surrounding region mixed among the diatribes and delusions. When a terithran kills an arcane spellcaster, it tears the heart from the corpse using its long claws and eats it; this appears to be the only food they consume. How terithrans reproduce is unknown—they have no discernible sexes and shun each other’s company. It is possible that terithrans are created through accidents of arcane magic, which would at least justify their bitterness, but there is no direct evidence for this hypothesis.
A terithran stands about four feet tall and weighs around 100 pounds.
