If your party likes Monty Python, or unkillable characters, this encounter is for you.
As the party is traveling from one location to another, they come across a stone bridge across a broad chasm. The bridge appears to be the only way across for miles in each direction. Obviously there are many ways across the gap, but the bridge will be the easiest passage.
If they look closely, there appears to be a shimmering wall on either side of the bridge that continues vertically into the sky, seemingly forever. The wall does not seem to do anything when they walk through it.
Standing at the center of the bridge is a knight in dark clothing. His helm and plate armor are worn and battered, and his sword looks heavily used. Think Guts from Berserk.
If the party approaches him, he plants his sword roughly in the ground, chipping away at the stones on the bridge. “None shall pass.”
If the party tries to convince him or attempts to cross, he repeats his phrase more vigorously. “None shall pass!”
Even if the party manages to make it across the chasm without the bridge, the Black Knight will appear in front of them, not allowing their passage.
Out on a Limb
Unable to avoid a confrontation with the Black Knight, the party can choose to fight or converse.
If they choose to fight, they will likely be confused to no end. The knight will fight mightily and deal great damage with each swing of his greatsword, but his limbs are not well attached. He’s not completely undead, but the way his limbs lop off make it seem as though he is. Stat block below.
With about 100 HP, each 25 HP down, the DM should remove a limb from the Black Knight. He is undeterred and even more motivated. Reduced to stumps, the knight will continue to jabber at the party, taunting them. Another way to run this is insanely high AC, low HP, just depends on the party makeup.
Play up the insults from the knight, especially as he continues fighting. Feel free to use some of these historic quotes.
Once dispatched and with only a torso remaining, the party could be on their way, OR they can listen to what the knight has to say.
Costs An Arm And A Leg
If the party inspected the shimmering wall, or asks a bit more about what is happening with the knight and his ability to lose limbs without losing blood, he will reveal the real situation.
Many years ago, the knight was attempting to elope with his girlfriend when they came upon this bridge. A cleric who disagreed with the marriage stopped the couple and gave them an ultimatum. If the knight could best the cleric, they could go free, but if not, the cleric would elope with the woman instead and the knight would be left there to die.
Out of the gate it was clear the knight was outmatched. As the cleric was about to strike the final blow, in a final loving act, the woman stopped him and offered to go willingly if she let the knight live. Unfortunately for the knight, the cleric abided, but with a catch. Slapping his hand hard into the stone, the cleric placed a Regeneration Gem in the bridge, giving strength back to the knight as long as he didn’t leave the area. It also seems to be messing with how he ages and he isn’t quite sure how many times he’s “died.”
Now the knight is worried that if he leaves the area, or pulls the gem from the bridge, he will die immediately. He is holding out hope that his one true love will return and they can build a dwelling on the bridge and live out their days.
The party could work to reunite the knight with his one true love (now 97 years old). They could also leave him where he is and be on their way. They could also figure out a way to make it so he can travel with the gem and find the woman that was taken from him all those years ago.