Fighting atop Firefinger
The top of Firefinger sits some 400' above the surrounding jungle floor. One can see approximately 36 miles before the curve of Aebir-Toril fades away from view. On a clear day, that is.
This is not a clear day. Looking down, you can no longer see the dozens of broken and mangled bodies of adventurers, tourists, tax collectors, missionaries, and hapless sods dropped from this height. But you remember the sight from your ground approach.
Footing is precarious atop Firefinger, particularly on a rainy day. This is going to be dangerous.
The purpose of this document
When you emerge atop Firefinger there is likely to be a potentially-lethal fight, with plenty of opportunity to plummet to an unpleasant death.
More importantly, there will be plenty of places for on-the-spot rulings to arise. I intend to set out, here, some thoughts about rulings that I anticipate coming up. My intention is to allow you--if you want--to play the `tactical game.' To make decisions while playing that reflect the competence and situational awareness your character--a trained adventurer--might have.
If you would rather the surprises, if you'd rather `immersive play,' then simply stop reading. There are many types of fun, and I simply hope to enable all of them.
-mca
Near the edge... (within 5')
- Taking an action. Any time a creature with neither fly nor climb speed takes an action near the edge they make a DC 10 concentration check. On a failed check, the creature's next roll has disadvantage, as they struggle to regain secure footing.
- Taking damage. Any time a creature with neither fly nor climb speed takes damage near the edge they make a DC 10 Dexterity or Strength save against falling off the edge.
Over the edge
- Clinging on for dear life. At any time a creature may take a reaction to grapple (q.v.) another creature within reach, if one of the two creatures is falling. If the grappling creature was falling before the grapple, both creatures are now falling. If the grappling creature was stationary, both are now stationary. The DC to grapple a willing, falling creature is 10. (Increase this DC by 2 for every additional creature; there may be mass grapple-chains occuring!)
- It's the fall that'll kill you! If a creature is compelled by any means to move such that they would fall (command, turn undead, &c.) they may make a DC 10 Wisdom or Constitution save to resist this compulsion in the face of certain death.
TIME! Marches on!
Combat time is strange. 6-second rounds, you can take reactions between your turns, and it's all happening somehow simutaneou-quentially?
Xanathar's Guide to Everything throws another wrench in the works by stating that "When you fall from a great height, you instantly descend up to 500 feet." (P. 77, emphasis mine.) This makes it largely impossible for another character to take an action to counteract one's fall which I find problematic. Experienced adventurers can see a comrade approaching disaster, not just experiencing it.
I propose the following modification: when falling, the movement associated with the fall occurs just before the creature's next turn.
There you go. More people have a chance to arrest a fall.