During mounted combat, I understand there are two possible options:

1. You can control your mount, in which case your mount cannot make an
   attack, or


2. You can opt to leave it independent (and controlled by the DM) in which case it can attack, but may do things you don't expect.

The text of find greater steed contains this excerpt:

Your steed serves you as a mount, both in combat and out, and you have an instinctive bond with it that allows you to fight as a seamless unit.

Does this phrase imply that there is some special way to control the steed beyond the above two normal options for mounts? Are steeds summoned in this way special in regards to the control rules, or is that just flavor text? It seems to me that an independent mount which can take actions that I cannot predict is not fighting as a seamless unit with me. Am I misunderstanding something?

The question here certainly provides an answer, but it's not satisfying since it assumes that the mount has to use one of the two above options and does not consider that there may be alternatives.

Yes, the summoned mount follows the normal rules for mounts

Per the description of find greater steed:

You summon a spirit that assumes the form of a loyal, majestic mount.

As you said, mounts can be handled in one of two ways: you can control the mount or you can allow it to act independently (per the rules for mounted combat):

While you’re mounted, you have two options. You can either control the mount or allow it to act independently. Intelligent creatures, such as dragons, act independently.

The summoned steed is a mount and thus follows this rule unless something else says otherwise. The spell actually says:

You control the mount in combat.

Which means that you have full control over the animal if you wish. Jeremy Crawford says that you can even choose to let it act independently if you wanted:

Find steed / find greater steed—when you ride the mount in combat, you decide whether it follows the rules for a controlled or an independent mount.

There are no other passages from the spell dealing with control of the steed and certainly nothing that would imply a special method of control that was unique to your summoned steed. Remember, spells do only what they say they do. There are no secret rules. If there was some special method for controlling the steed, the spell would say so and detail how it worked.

So, the spell grants no special control method for summoned steeds.

There is also nothing in the description of find greater steed that has any friction or conflicts with the normal rules for mounted combat.

Only find steed says anything about fighting as a seamless unit

Contrary to your question, only find steed has the following passage:

Your steed serves you as a mount, both in combat and out, and you have an instinctive bond with it that allows you to fight as a seamless unit.

The only thing like it that find greater steed says is the quote about controlling the mount which I quoted above.

However, even if that text was in find greater steed, fighting as a seamless unit is exactly what the controlled mount option is. Controlled mounts normally have to be special creatures that were trained to accept a rider.

Jeremy Crawford has clarified and made it clear what that passage was intended to mean:

The spell says that you and the steed fight as a cohesive unit and you
can communicate with it and it serves you.

Really what that means is, it is up to you [...] whether to control it
or let it act independently

Your bond with your steed allows you to fight as a single unit with it (controlled), but "allows" does not mean that you always have to be fighting as a single unit. Hence you can still have the mount act independently and be two individual fighters as opposed to (essentially) one.

Regardless, the conclusions for find steed are the same as for find greater steed: they follow the normal rules for mounts.

The mount only acts "randomly" if you let it act independently

You control the mount when you want to. When you control it, it doesn't act randomly. If you don't want the mount to act in a way that you as a player don't control, then you should choose to always control it. However, it is worth noting that even when the DM is controlling the creature, it is not going to be cating randomly. It is still going to act according to it's intelligence and what its and possible your best interest.

Having a summoned steed has plenty of benefits over a normal horse

The spell itself grants many advantages to using the spell to summon a steed as opposed to buying a horse:

• The steed is also affected by spells that the rider cast (while mounted) that target only the rider


• Telepathic communication with the steed


• Not having to purchase a steed


• Being able to resummon the steed if it dies as opposed to having to replace it


• Being able to control the mount without training


• Increased intelligence


• Option to choose the form of your steed

The first bullet alone is huge for spellcasting and allows for some really neat synergy in battle. But as a whole the summoned steed is unambiguously better than mounts you can find or buy.

Form matters a lot

Not only do the mounts here have better stats than a common horse, some of them have flight which is a huge benefit in many cases. Having at-will flight is so good it is often seen as being over-powered and ways to get it are very limited.

Not only that, but the cosmetics matter. Being able to choose the form of your steed is an advantage in and of itself. Where else are you going to find a tame saber-toothed tiger to ride? Or a rhinoceros?

The steed is subject to all the usual rules for mounted combat.

The excerpt you quote is there to indicate that your character has an unusually strong bond with the steed. The intent of the spell is that the steed is completely loyal, and that its wishes are likely to be your wishes. It serves you and will always let you use it as a mount. And when you use it as a mount in combat, the usual rules apply.

You've highlighted the relevant passage from the rules on mounted combat. When riding your steed, you have to make a choice:

While you're mounted, you have two options. You can either control the mount or allow it to act independently.

If you choose to control the mount, its initiative becomes yours. The advantage is that you can now interleave the mount's movement and actions with your own. The disadvantage is that the mount can only take the Dodge, Disengage, or Dash actions.

If you choose to allow it to act independently, it rolls its own initiative in combat and has a full turn including all of the usual action choices for a creature of its type. The disadvantage here is that your mount now moves and acts on its own turn and not yours.

That doesn't mean that the steed will act contrary to your wishes. It might. It's an NPC, so that's really up to the DM. But the DM should take into account that this is a creature that serves you, can hear your thoughts, and sense your desires. Since the steed is supposed to be completely loyal to the Paladin, many DMs (including me) will simply ask the player to take control of the steed's turn when it's acting independently.

See the following video for a detailed explanation of mounted combat from Jeremy Crawford:

https://www.youtube.com/watch?v=99tX6tmc73Q