During COVID,
Matt Johnson hosted a series of Collabo Dungeons. Participants selected a room and posted a description and a possible encounter on Matt's
website.
Here is what I posted in 2020.
Location Seven. The Twins.
There are two women, twins, in the pit. They are identical in all ways save one. One woman wears a lead ring. When they become aware of the characters, they will both shout out for help. When the characters look in the pit, they will hear the following orders:
Twin with the ring: "Kill her! She's a demon!"
Twin without the ring: "Kill her! She's an idiot!"
They are both at the bottom of the pit and represent no threat to the characters in this state. They are both bloodied and bruised from the fall and each has a blackened right eye.
If the party rescues them, they will find out the following information. Twin One, the one with the ring is named Meredith. She entered the dungeon with her friends in search of treasure. She found a gold ring in area 8 and after discerning no purpose to it, put it on. She was pushed by a monster into the pit.
Twin Two, without the ring, was a doppelganger hiding in Area 8. To take on Meredith's form, she ambushed her by pushing her into the pit. Unfortunately for the monster, Meredith grabbed it's wrist as she fell and both ended up at the bottom. As the doppelganger took her form, Meredith shouted "Begone!" which the ring of wishes interpreted as a command against the monster. Since the doppelganger was in mid-transformation into Meredith, the ring fixed it in that form before turning to lead. The doppelganger is now an exact copy of Meredith.
The twins have found combat against each other to be profoundly lethal, as they mirror each other's moves perfectly, hence the matching black eyes. They will not fight each other. They will join the party to escape the dungeon.
At the time, I posted Meredith as unstated. I had envisioned Meredith as a young character, one who needed more wisdom. I supposed that she was an accursed thief or perhaps a mage. In rolling them up, I decided they were fighters.
Them... They... In the room description, we find out how Meredith became a twin.
I've given one of them a new name, Mercy. They have matching stats, experience and class, plus a few other surprises. In their time adventuring together, they have found a pair of Bracers of Defence, AC 4. In addition to this, they both have magic swords. These hand-and-half swords are also a matched pair like the Bracers. Each woman is vaguely annoyed that every treasure they find is a matching set. This is because they both want and value the same items. In reality, they have ignored other treasures as worthless because it wasn't what they wanted or valued.
Meredith wields the sword Nine Lives. It is only +1 but it prevents her from being flanked or backstabbed. If someone attempts to flank or backstab her the attacker must make a saving throw versus parayzation. If the attacker fails this save, Meredith magically spins to face the attacker, negating their bonus. This can happen as many times in a combat round as there are flanking attackers. This does not allow Meredith an extra attack unless the person flees.
Mercy wields a sword named Calico. This sword also has powerful magic. On the first swing in combat it is a +1 to attack and damage. On the next swing, it is +2. This continues until Mercy receives a +3, at which point the sword resets to +1. Mercy is a brutal fighter. She often draws Calico and makes two flourishing swings, which sets the sword to +3 from the get-go.
The Bracers and the Swords are meant to be used by a single person, florentine style, not two different people. The Swords' special abilities work together, making the wielder nigh unstoppable.
The Twins have several other nasty traits. First, Meredith is the original human and is identifiable by the lead ring. This is a helpful trait, sometimes.
Next, the ring cannot be removed by any mechanism except a wish. Grabbing at the ring will unleash woe on the thief. They must save versus death, or collapse in a seizure for 2d6 rounds. They take no damage but will be horribly sick once the seizures end.
Heaven help the person who tries to use a tool to get the ring, like a bolt cutter or knife to cut the ring (or finger) off. They will also need to save vs. death. If they succeed, they merely have the seizures described above. If they fail, they burst into flames for 1d6 points of damage per round AND have 1d6 rounds of seizures. Unless someone helps them, they will burn for the entire duration of the seizure.
The third dangerous trait is Mercy only uses that name in Meredith's presence. In Meredith's absence, she reverts to using "Meredith". Since she is an exact copy of Meredith (except the ring) and knows everything she does. This can cause chaos for a party. Or a lover. Mercy does this to assume Meredith's place as if they were the same person. She does not intend harm to the people she fools, she only wants her rightful place the original woman.
For this reason, the real and original Meredith is unperturbed by Mercy's behavior and ignores it. She will honor Mercy's promises in her stead and will easily forgive and forget other's missteps regarding Mercy's unseemly behavior. Mercy's adoption of Meredith's place is confusing, not malicious. They are effectively the same person and have the same goals and desires, but do not intend to share anything.
Mercy and Meredith are pseudo-cursed to stay together. Since they are a matched pair, they always assume the other will be there for them. Separated, they suffer shortcomings from this expectation. Together, they are far more powerful and successful.
Occasionally, circumstances cause them to come to blows. They will only slap, punch, and kick as their blows land on each other unerringly. They will not use weapons on one another as it would be instantly fatal. This quirk can foil charms, illusions, and other mind-altering magic as they see each other as the same person and will be resistant to interpreted self-harm.
