Can the Revised Ranger’s Beast Companion be an independent mount?

The mounted combat rules say that you can either control a mount, making it move on your turn — but its action can only be Dash, Disengage, or Dodge — or have it be independent, meaning it can do its actions but you have no control over it.

Now, if a ranger uses their Beast Companion as a mount, could they direct it as they usually do when unmounted and still have its full array of actions, since the beast still acts on their own initiative?

Mount size calculations

In our latest session a party member purchased a baby triceratops. According to dnd sources baby triceratops is a medium sized being (according to TOA) and my party member is also medium size.

The player asked whether being mounted on the triceratops is considered a large creature or still medium. Are there any official rules according to the sizes of mounted beasts?

Thank you in advance.

Why stand on a mount?

Epic Ride checks confer the ability to stand on a mount. What mechanical benefit does this confer? The only description given in the SRD is:

“This allows the character to stand on his or her mount’s back even during movement or combat. The character takes no penalties to actions while doing so.”

but I am unaware of anything that is actually gained from doing this. Is this a blunder? A recent and related answer from KRyan found nothing.

Can a neutral or even a good-aligned character realistically have a nightmare as a mount?

So I’ve got a player in my campaign who’s character, of chaotic neutral alignment and level 16, has been in search of a magical mount. After much research in game the character has grown an obsession for Nightmares.

Their story arch is bringing them to the Fire plane soon because of a city known for its magical beast/ servant trade there. Story-wise, there’s no reason why she wouldn’t be able to find one for purchase and begin negotiations. As the DM, I have no problem at all with this and actually promote the creative way of obtaining one.

My only question is how this may affect her, or if the nightmare will/won’t serve her.

All I’ve been able to find regarding this has been tips like this one from realmshelps.net:

Nightmare, Lesser: A nightmare is a horselike creature of evil; a good-aligned owner who makes an investment in a lesser nightmare soon discovers that the mount does not serve him and escapes at the first opportunity. Lesser nightmares are bred from their more powerful brethren. Not as headstrong or as capable of traveling between the planes at will, a lesser nightmare still can carry its passenger into other dimensions.

She for sure isn’t a good-aligned character, but isn’t evil either.

Can a non-evil character realistically have a nightmare as a mount?

Exchanging control of a mount

This is a situation that came up recently in a game I play in. Two player characters were riding an elephant in combat. The elephant was acting as a controlled mount under control of one of the riders, who was higher in initiative order than the second. During their turn, the controlling rider had the elephant move part of its speed and take the Dodge action. They then handed the reins to the other rider and dismounted.

What should the second rider be able to do on their turn? In our game, the second rider had the elephant move the remainder of its speed and didn’t give it a new action. I feel this is reasonable, but I’m curious whether the rules can be read to give more specific guidance for situations where the controller of a mount changes during combat. In particular, does the initiative order of the first controller, the second controller, and the mount affect what can happen, and how?

While riding a mount summoned by Find Steed, when does the caster choose whether the mount is controlled or independent?

Other Q&As on RPG.SE have discussed the by-now-familiar rules for mounted combat, including the differences between controlled and independent mounts. See, e.g., When can you choose to control a mount? Mounts summoned via find steed, however, are a special case. Per this 2018 guidance from Jeremy Crawford,

when you ride the mount [summoned via find steed] in combat, you decide whether it follows the rules for a controlled or an independent mount.

What remains unclear, however, is precisely when a caster who is already mounted on the summoned steed may, or must, make that choice. For example, it could be:

  • When the DM calls for initiative rolls.
  • Only on the caster’s first turn.
  • Only the mount’s first turn.
  • On any turn the caster takes.
  • On any turn the mount takes.
  • On any turn whatsoever.

Some of these options would require the caster to choose only once and stick with it. Others would conceivably let the caster change her mind each round, or even multiple times each round. Which (if any) is the correct way to handle mount control using find steed?