A list of bad guys for my game and any Oriental Adventure setting – in particular a Japanese themed setting.

ONI

Oni were the demonic monstrosities that made up the most powerful forces of the Shadowlands. Oni only gained a physical presence in the realm of mortals if spawned by an Oni Lord or by being summoned from Jigoku by someone willing to share their name in exchange for power. Oni are a race of evil spirits, native to the Jigoku, that (generally) manifest physical bodies based upon the shapes and desires of humanoid mortals with an unmistakable preference for giant kind. In pure spirit form, an oni is nothing but a disembodied evil longing for the sins of the flesh. In this form, oni are harmless and invisible.

The majority of these bodiless oni were once kami who failed their wards, or more often, who deliberately abandoned them.  As punishment, they were stripped of their ability to form a physical body and then cast into the void. Rarely, a mortal creature’s soul can become a disembodied oni upon death, or in even rarer cases, after a truly evil individual has undergone a particularly vile ritual that ends in suicide. These oni are more often destined for positions of great power and strength than most.

Although oni have little concern for other creatures, they do have a sense of honor and pride, and resent being implicated in crimes they did not commit. For instance, the tale is told of a yakuza gang who convinced a village that an oni had committed certain crimes. In truth, the yakuza themselves were responsible. When the villagers began to hunt the oni, it became enraged, vowing to seek out and destroy the yakuza. (The oni enjoyed its notoriety as the scourge of the countryside, but it was not about to accept the blame for the yakuza gang’s actions.) The oni made peace with a group of sympathetic humans, who helped the lesser spirit track down the yakuza. Following the yakuza’s defeat, the oni honorably parted company with the humans. Then it resumed its evil ways.

In Dungeons and Dragons, the most iconic of this species of evil creature is the Ogre Mage – an oni who has taken on the form of an ogre.  Though there are unique and specific oni almost any humanoid or giant can become an oni.  The following template provides some guidance to building an oni from scratch or modifying an existing creature.

PHYSICAL DESCRIPTION

Oni are ferocious lesser spirits who use their awesome strength and magical abilities to dominate and terrorize the regions they inhabit.

The common oni stands 7 to 8 feet tall, resembling a thickly-muscled humanoid whose arms and legs are covered with coarse hair. Their hands end in dirty, thick talons, and hooked toenails grow from their wide feet. Their skin is normally red, but other colors have been noted, including green, black, orange, and purple. Blue-skinned oni also exist, but these are more commonly known as ogre magi, because they have as much in common with the western ogre as they do they with eastern oni.

The features of the common oni are fearsome to behold. They have from one to three bulging eyes and broad, pointed ears. One or two thick horns may sprout from their foreheads. Many oni wear shoulder-length hair – usually silver, black, or green – which sometimes is tied in long braids that drape down their backs. Long golden or ivory fangs line their mouths.

An oni’s garb imitates the clothing of the local human population. If an oni band dwells near a military outpost, the lesser spirits usually wear armor pieces, including metallic arm and leg bands and even military insignia that have been taken from murdered soldiers. If an oni band lives near a poor farming community, they usually don peasant smocks and sandals. In any case, an oni’s equipment and clothing is always more ragged and filthy than that of his human counterpart.

Common oni can speak the language of their kind, as well as the languages of tengu, bakemono, hengeyokai, and the local human population. Their voices are deep, resonant, and very loud. An oni’s snore rumbles like thunder, while its laugh is powerful enough to shake the leaves from the trees.

This template may be applied to any humanoid, giant or fiend.  Unless otherwise stated the original creature retains all its abilities. Fiends of all types make good oni examples. More details on oni here.  Oni should each be unique as well. For example, outside these shared traits, one may use a tamari in battle while another is straightforward combatant, and another uses a taiko drum etc.

• Type. The base creature gains the Fiend (oni) type in addition to its other keywords.
• Size. Oni are always Large size or larger (with few exceptions).  If the base creature is smaller than Large it increases in size gaining the appropriate increase in hit points.
• Alignment.  Oni are always evil though they may be any of Lawful, Neutral, and Chaotic they tend to be Lawful Evil. Those that are chaotic evil gain the “variable resistance” trait.
• Abilities: Strength.  Oni are brutal and cruel and the base creature’s Strength is raised to 19 if not already that high (or higher).
• Senses. The base creature gains darkvision out to 60 feet if it does not already have it. If it has a CR of 10 or more it can see also see invisible as the spell.
• Damage Resistance. The creature gains resistance from bludgeoning, piercing and slashing damage that are not jade/honourable.
• Language. All oni speak Common and Spirit Tongue (Oni) in addition to any language the base creature had (usually giant, abyssal or infernal).
• Discorporation. Unless killed using a special weapon – like a mortal blade or a jade enchanted weapon – a destroyed oni turns into black smoke before dissipating. It gains a new body in 1d10 x CR days, regaining all its hit points and becoming active again. NB: This trait only applies outside of Jigoku.
• Demon Blood Magic.  The creature gains the innate spellcasting trait. The oni’s innate spellcasting ability is Charisma (spell save DC 8 + proficiency bonus + CHA score).  The oni can innately cast the following spells, require no material components in addition to any spells the base creature already has. An example list below:
  • At will: darkness, invisibility
  • 1/day each: charm person, cone of cold, gaseous form, sleep
• Magic Weapons. The oni’s weapon attacks are magical.
• Regeneration. The oni regains a number of hit points equal to its Challenge rating (minimum of 10) at the start of its turn if it has at least 1 hit point.  If the oni takes jade based damage, this trait doesn’t function at the start of the oni’s next turn.
• Shapechanger. The oni can use its action to polymorph into a Small, Medium or Large humanoid it has seen, or back into its true form. It’s statistics, other than its size, are the same in each form.  Any equipment it is wearing or carrying isn’t transformed.  It reverts to its true form if it dies.
• Wisteria Aversion. Oni avoid the fuji flower as its fragrance makes them ill. If forced to take any action while within line of sight of a wisteria plant the oni has disadvantage on attack rolls, ability and skill checks.
• Variable Resistance. Chaotic Evil oni gain this reaction – “As a reaction to taking energy damage the oni gains resistance to that damage type for 1 minute. This resistance can be overwritten by other reactions in later combat rounds”.

Finally, it gains a claw attack appropriate for its size, Challenge Rating, and Strength if it does not already have this attack option.  This is a slashing based Strength attack.

A note on spell casting.  Though a generic list of base spells have been provided it is exactly that – a generic list. Just as oni tend to have unique powers – no two oni are the same – their spell list should reflect this. For example, a spider-themed oni may have unique spells which makes their webbing razor-sharp or their web cocoon to be as hard as adamantine and spew acid to anything in the cocoon. At a minimum oni have access to blood magic spells as part of their spell list.

Additionally, powerful oni will have the additional blood magic trait which allows them to manipulate and overcharge their demon blood magic ability. As a guideline, only oni of CR 7 or higher should have demon blood magic.

Example Oni

Here is a list of oni I created for my game.