Adventure Hook: The Oni Assassin

This week: a relentless assassin, a cursed forest, and a shadowy showdown.

Adventures can take many forms. Sometimes you’re sent out in search of adventure–and sometimes adventure comes in search of you. This week, we’ve got an adventure hook for you that sees the player characters hunted by an Oni assassin. We leave the reason for it up to you–whether it’s hunting down the party because the Oni was hired to do so, or because it’s some kind of Predator-esque game, you decide. But here’s a few ways to make your players feel that the hunters… have become the hunted.

This adventure is designed for players of 7-10th level. See below for suggested guidelines.

This week, adventure comes to the PCs’ doorstep, when an oni assassin comes calling. The PCs are hunted by an Oni, as he takes on the form of various, nondescript humanoids in an attempt to catch the party off guard. It is a deadly game of cat-and-mouse, one which the Oni escalates by driving opponents to a blighted forest, where he hopes they will be easier prey…

The key to this adventure hook is to  use the Oni’s shapeshifting abilities. They might appear as any unassuming NPC after the initial attack. The trick is to never stay engaged for more than a few rounds before retreating. The Oni’s regeneration gives it a big edge in a battle of attrition, and this is a rare chance to actually make your players feel it. This Oni is a patient hunter, and is playing the long game. He follows them, trying to hound them into leaving the city for their safety–if the PCs prove unwilling to leave, he approaches them in disguise, convincing them to set a trap for the “demon” on their trail.

If he succeeds in getting them to leave the city, he directs them to a Blighted Forest nearby, where he hopes the twisted creatures within the forest will weaken them enough that he and an ally might be able to move in for the kill.

But if the PCs are cunning, they may be able to turn the assassin’s trap against him…

Read on for more details. or skip to the end for all the stats you’ll need!

Hunters & Hitmen

The adventurers have come to the town of Markath’s Landing, a prosperous lakeside town. The PCs are exploring the tavern and find themselves approached by a mysterious stranger who wishes to speak to them about an endeavour of the utmost importance. Indeed, the fate of the world may hang in the balance. And so, speaking these hushed words, the figure retreats to a private room where they may speak in person with the PCs about this daunting task.

This is, of course, a trap. The mysterious figure is in reality Daon, the Patient Hunter, an Oni assassin who specializes in dispatching heroic targets. He has been stalking the PCs for some time, observing them from disguise and waiting for a moment to spring his initial attack. He chooses a setup familiar to adventurers the world over–luring them in with promises of wealth and danger. When they have arrived, he shrouds the room in darkness and uses his magics to try and take out one of the PCs as quickly as possible, opening with a Cone of Cold and then following up with as vicious an attack as possible against the most fragile-seeming of the PCs.

However, he knows that some targets may prove to be more difficult than others, and if the element of surprise and his initial area of effect spell don’t help him eliminate his prey, he’s more than prepared to retreat, using a combination of invisibility, darkness, and either the entrance to the room or one of the windows to make good his escape once he’s brought below half of his hit points. If he truly seems cornered in the room, he’ll use gaseous form to escape up the chimney and away onto the breeze.

Then he relies on his natural regeneration to bring him back to fighting form, and will attempt to confront the PCs again. If any of them seem especially weakened after the initial encounter, he may return to attack before they even have a chance to complete a short rest–as he’ll be back to full health before the PCs can spend their hit dice, using his shapeshifting ability to get close to the PCs before they are aware.

Shapeshifters have a certain Mystique, don’t you think?

This time he attempts to separate the party if possible. Striking from surprise–however, if they continue to drive him off, he will settle for harassing them. Never letting them pass a day unmolested. If they leave Markath’s landing, he’ll follow them. Daonos is a skilled tracker, and unless the PCs take special precautions, should have no difficulty following them. Once they’re out of the city, he’ll try to attack them at range, using his crossbow, invisibility, darkness, and stealth to try and skirmish with the PCs–always staying at range. But trying to drive them towards the nearby woods.

If the PCs don’t leave the city and Daonos cannot outfight them, he will instead adopt the guise of a monster hunter–he will allow some time for paranoid PCs to settle, before reaching out, claiming to be in pursuit of a monster who can take the shape of others. He may even go so far as to act paranoid of the PCs, accusing them of being the Oni if he thinks it’ll help his credibility. He explains that he’s set a trap for the monster, and since it seems fixated on them, perhaps they can act as bait. This trap, is, of course, set in the nearby woods.

Clever players might try and see through his ruse, in which case some opposed Deception vs. Insight checks might be called for–thsoe who succeed will realize that he’s clearly trying to lure them into a trap–and that this might be their opportunity to reverse it.

Can’t see the Oni for the Trees

As mentioned above, the Oni tries to drive the PCs deeper into the forest, where an ally waits out of sight of “civilized” folk. Here the Oni hopes that the addition of his ally, and the oppressive aura that hangs over the forest (emanating from a cursed ruin that the Oni uses as a killing ground) will weaken his prey enough that they’ll be easy pickings.

However, this is where the PCs have a chance to reverse the fate of the ruins. The Oni stalks them, firing at them with his crossbow and attempting to lure them deeper into the cursed woods. However, clever PCs might be wise to the fact that this is a trap. They may have sussed it out from the city, or those who can succeed at a DC 15 Insight check can recognize that the Oni is trying to lure them to a specific spot with his actions.

The other thing the Oni is trying to do is to get the PCs to expend precious resources as well. He’ll fire off a shot or two, or leave himself open to one attack in an attempt to draw out spells/limited use abilities from the PCs before retreating into hiding again and regenerating. A similar check will reveal this as well.

Proactive PCs can get an idea of the direction he’s leading them in–and may try to use either stealth to hide their presence and/or survival to try and get an idea of where he might be leading them. A DC 16 Survival check will give the PCs a good enough idea of the direction the Oni is herding them. A DC 14 Nature check will reveal the cursed nature of the woods once they get close enough to where the cursed ruin is–they can see before they enter its aura that the ruins are twisting the woods around them.

A DC 12 Religion Check will reveal that this was once a temple to a nature deity, but it has long been desecrated–where once a clear pool of water stood at its heart, a brackish, blood-tainted pool waits instead. It casts a heavy aura on the place, slowing the movement speed of all nonevil creatures by 10 feet per round, unless they succeed on a DC 12 Charisma saving throw. It also hungers for blood–any character injured while standing within 10 ft. of it must make a DC 12 Charisma save or be at Disadvantage on all ability checks and attack rolls until the end of their next turn.

However, this ruin may be turned against the Oni. PCs with Religion can attempt to purify the water with a sacred rite–requiring them to use their action to make a DC 16 Religion Check. Characters with Nature can make a DC 15 Nature check to try and get the water flowing again, as this too will wash away the brackish and corrupted water that is the source of the curse. If the water is purified, all nonevil creatures within 60 ft. of the well are healed for 4d8+8 hit points and have advantage on attack rolls and ability checks until the end of their next turn. Additionally, if the Oni is splashed with purified water (a ranged attack action out to 10 ft. or the PCs can get clever and use bottles or the like to make grenades, in which case normal thrown weapon rules applies), Daon’s regeneration ceases to function for one round.

Once the PCs defeat the Oni, they can more readily purify the pool if they haven’t done so. They also find a +1 Glaive (the Oni’s weapon), and the 2,000gp in rubies that was used to secure the Oni’s services. As for who sent the Oni in the first place, there is no sign. The Oni bears only a strange glyph–an arcane sigil, presumably through which his employer would contact him. Who and why, we leave to you!

Daon, the Patient Hunter

Large giant, lawful evil

Armor class 16 (chain mail)
Hit points 110 (13d10 + 39)
Speed 30 ft., fly 30 ft.

Saving throws Dex +3, Con +6, Wis +4, Cha +5
Skills Arcana +5, Deception +8, Perception +4, Stealth +3, Survival +8
Senses darkvision 60 ft., passive Perception 14
Languages Common, Giant
Challenge 7 (2,900 XP)

Innate spellcasting. The oni’s innate spellcasting ability is Charisma (spell save DC 13). The oni can innately cast the following spells, requiring no material components:
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 one regains 10 hit points at the start of its turn if it has at least 1 hit point.

Actions

Multiattack. The oni makes two attacks, either with its claws or its glaive.

Claw (Oni Form Only). Melee weapon attack: +7 to hit, reach 5 ft., one target. Hit: 8 (1d8 + 4) slashing damage.

Glaive. Melee weapon attack: +8 to hit, reach 10 ft., one target. Hit: 16 (2d10 + 5) slashing damage, or 9 (1d10 + 4) slashing damage in Small or Medium form.

Crossbow. Ranged weapon attack: +4 to hit, range 100/400 ft., one target. Hit: 11 (2d10) piercing damage, or 5 (1d10) piercing damage in Small or Medium form.

Change shape. The oni magically polymorphs into a Small or Medium humanoid, into a Large giant, or back into its true form. Other than its size, its statistics are the same in each form. The only equipment that is transformed is its glaive, which shrinks so that it can be wielded in humanoid form. If the oni dies, it reverts to its true form, and its glaive reverts to its normal size.

Daon’s Companions

Depending on the level of your party, we recommend the following as ally/allies for Daon in his showdown with the PCs at the ruins.

7th level party: Kaulath the Scaled Spear

8th-9th level party: Kaulath the Scaled Spear and Crusher Curg

10th level party: Kaulath, Curg, and Varthix the Nightmaiden.

Kaulath, Scaled Spear

Medium humanoid (lizardfolk), neutral

Armor class 15 (natural armor, shield)
Hit points 78 (12d8 + 24)
Speed 30 ft., swim 30 ft.

Saving Throws Con +4, Wis +2
Skills Perception +4, Stealth +5, Survival +4
Senses passive Perception 13
Languages Draconic
Challenge 4 (1,100 XP)

Hold breath. The lizardfolk can hold its breath for 15 minutes.

Skewer. Once per turn, when Kaulath makes a melee attack with his trident and hits, the target takes an extra 10 (3d6) points of damage, and Kaulath gains temporary hit points equal to the damage dealt.

Actions

Multiattack. The lizardfolk makes two melee attacks, one with its bites and one with its claws or melee weapon, or two with its trident.

Bite. Melee weapon attack: +5 to hit, reach 5 ft., one target. Hit: 6 (1d6 + 3) piercing damage.

Claws. Melee weapon attack: +4 to hit, reach 5 ft., one target. Hit: 5 (1d4 + 3) slashing damage.

Trident. Melee or ranged weapon attack: +5 to hit, reach 5 ft. or range 20/60 ft., one target. Hit: 6 (1d6 + 3) piercing damage or 7 (1d8 + 3) piercing damage if used with two hands to make a melee attack.

Crusher Curg

Medium humanoid (goblinoid), chaotic evil

Armor Class 17 (chain shirt, shield)
Hit Points 65 (10d8 + 20)
Speed 30 ft.

Skills Intimidation +2, Stealth +6, Survival +3
Senses darkvision 60 ft., passive Perception 11
Languages Common, Goblin
Challenge 3 (700 XP)

Brute. A melee weapon deals one extra die of its damage when the bugbear hits with it (included in the attack).

Crusher’s Courage. Curg has advantage on saving throws against being charmed, frightened, paralyzed, poisoned, stunned, or put to sleep.

Surprise Attack. If the bugbear surprises a creature and hits it with an attack during the first round of combat, the target takes an extra 7 (2d6) damage from the attack.

Actions

Multiattack Curg makes two melee attacks.

Morningstar Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 12 (2d8 + 3) piercing damage.

Javelin Melee or Ranged Weapon Attack: +5 to hit, reach 5 ft., or range 30/120 ft., one target. Hit: 10 (2d6 + 3) piercing damage in melee or 6 (1d6 + 3) piercing damage at range.

Varthix, the Nightmaiden

Medium fiend, neutral evil

Armor class 17 (natural armor)
Hit points 112 (15d8 + 45)
Speed 30 ft.

Skills Deception +7, Insight +6, Perception +6, Stealth +6
Damage resistances cold, fire; bludgeoning, piercing, and slashing from nonmagical attacks not made with silvered weapons
Condition immunities charmed
Senses darkvision 120 ft., passive Perception 16
Languages Abyssal, Common, Infernal, Primordial
Challenge 5 (1,800 XP)

Innate spellcasting. The hag’s innate spellcasting ability is Charisma (spell save DC 14, +6 to hit with spell attacks). She can innately cast the following spells, requiring no material components:
At will: detect magic, magic missile
2/day each: plane shift (self only), ray of enfeeblement, sleep

Magic resistance. The hag has advantage on saving throws against spells and other magical effects.

Happy Adventuring!

Author: J.R. Zambrano

Bell of Lost Souls Staff Writer and DM, J.R. covers RPGs of all stripes and on occasion eats sandwiches. You can ask him about either at [email protected]