How does the second benefit of the Mounted Combatant feat interact with total cover?

Question

The second benefit of the Mounted Combatant feat (PHB, p. 168) lets you force an enemy to attack you rather than your mount when they attempt to attack the latter. What happens if you do that while you, but not your mount, is in total cover?

Answer 1

The rider gets no benefits from total cover because a redirected attack is not a direct attack but an indirect one; alternatively, this is a case over specific over general

The rules on Cover state:

[...] A target with total cover can't be targeted directly by an attack or a spell, although some spells can reach such a target by including it in an area of effect.

I would say that redirecting an attack from your mount to yourself is not, in any way, making it a direct attack against you. The attack has indirectly targeted you and thus total cover provides no benefits.

---

Unfortunately covers do not stack:

If a target is behind multiple sources of cover, only the most protective degree of cover applies [...]

Thus having total cover does not also give you ¾ cover. This means that the rider will be benefitting from no forms of cover whatsoever and the attack roll will happen as normal. Though what counts as the "most protective degree" could be argued to be ¾ cover that's something I'm less sure of and is somewhat explained in the question "What constitutes the most protective degree of cover?".

---

Alternatively you could explain this as the Mounted Combatant feat allowing you to target somebody even if they do have total cover. This would just be an example of specific over general where normally you can't target somebody with total cover but the Mounted Combatant feat specifically forces the rider to be targeted (barring any even more specific rule). Note that the feat says the attack targets you, not that it targets you only if the attack could otherwise do so legally. Thus the feat results in you being targeted by the attack even if it would usually be illegal.

This angle is the approach taken in user jgn's answer

Answer 2

You can't see the attack coming.

Unless you're in total cover inside impenetrable transparent windows (what are you riding, the Popemobile?), you can't see that your mount is getting attacked, so you can't do anything about it.

No, the feat doesn't say you have to see the attack coming. This is a corner case that the rules shouldn't be expected to address--any "normal" kind of mounted combat requires you to see your surroundings. But it's self-evident that your character can't react to something they're totally unaware of.

(There is the alternate possibility that it's like the Lucky feat, where your character doesn't have to be aware--the universe is just doing them a favor. But the Lucky feat is called "Lucky" and describes its effect as "inexplicable luck that seems to kick in at just the right moment". Mounted Combatant says nothing of that kind.)

And anyway, you aren't a valid target.

If you are riding the Popemobile and want to take a bullet to save your car, you still can't, because you're stuck inside the car. You can't interfere with attacks that are happening outside your bulletproof box.

Here's the total cover rule:

A target with total cover can't be targeted directly by an attack or a spell, although some spells can reach such a target by including it in an area of effect.

I read the second clause here as clarifying the meaning of "targeted directly": to "target, but not directly" means to include the target in an area of effect. Forcing someone to target you instead of your mount causes them to target you directly, not with an area of effect.

Which is to say, if you're in total cover, the attack can't target you and so you can't force it to target you.

Answer 3

The circumstances of the attack roll (including cover) are irrelevant in this case-- the rider does nothing to the attacker. The feat applies specific rules which override the general rules.

As Medix2 cited, the relevant rule about cover is

[...] A target with total cover can't be targeted directly by an attack or a spell, although some spells can reach such a target by including it in an area of effect.

Emphasis mine. This describes the situation with respect to the attacker-- they cannot choose to even try to hit the rider, as the rider has full cover and can't be targeted. But when using this element of the Mounted Combatant feat, this is not what's happening.

We're not talking about something like taunting the attacker so that they choose to try to hit the rider instead of the mount-- total cover makes that impossible. Instead the rider is causing themselves to become the target. RAW, this necessarily means that the rider must be a valid target, else they could not be a target at all. The ruling then has to be either that the total cover doesn't apply, or that this element of the feat can't be used in this situation. Going by the specific-beats-general standard suggests that the former resolution is better supported.

---

Flavor-wise, your gnome friend's strategy doesn't make much sense. There are no saving throws or skill checks, so this is something that the rider is doing, not something they are doing to the attacker. They aren't magically diverting arrows and sword strikes away from the mount and towards themselves, like a magnet altering a flight path. They're moving their mount and their own body to intercept the attack in order to protect the mount.

It might plausibly be ruled that that can still happen when inside of a hut which is itself mounted on the mount, but then it would be the hut becomes the target (much like there is little difference between attacking a creature or attacking a creature's armor). A case like that can be handled by giving the hut HP or AC, or by implementing the optional attacks-that-miss-the-target-still-hit-something rules.

But absent something like that, allowing total cover to persist while using Mounted Combatant in this way creates a trivial way to produce a perfect, infinite tank.

Answer 4

The specific overrules the general.

The general rule:

A target with total cover can't be targeted directly by an attack or a spell, although some spells can reach such a target by including it in an area of effect.

However, when you use Mounted Combatant you modify the target, this overrides the general rule:

You can force an attack targeted at your mount to target you instead.

Sorry gnome, you played yourself.