Medium PC, Huge Mount: Where do I sit?

Question

So, most people who have dealt with mounts and specifically "Large" mounts always reference these two sentences:

A horse (not a pony) is a Large creature and thus takes up a space 10 feet (2 squares) across. For simplicity, assume that you share your mount’s space during combat.

In a game I'm partaking in, I, a medium sized PC, have gotten my hands on a Huge mount.

Huge has the following space:

\begin{array}{|c|c|} \hline \hphantom{•} & \hphantom{•} & \hphantom{•} \\ \hline & & \\ \hline & & \\ \hline \end{array}

So, naturally, I as medium, would fit as follows:

\begin{array}{|c|c|} \hline \hphantom{•} & \hphantom{•} & \hphantom{•} \\ \hline & • & \\ \hline & & \\ \hline \end{array}

Now, would I as a medium character, need a reach weapon to even be able to hit something adjacent to my Huge mount, or does the line about "for simplicity, assume you share your mount's space during combat" mean that I can hit someone technically 10ft away from me? And conversely, allow enemies to hit me from 10ft away without a reach weapon?

Answer 1

for simplicity, assume you share your mount's space during combat

This means that your Space stat takes on the value of your mount’s Space stat, i.e. 15 ft. Your reach doesn’t change, so in this case you have a 15-ft. space with a 5-ft. reach, so you threaten the 16 squares surrounding the 3×3 square. If you have a reach weapon, you don’t threaten those 16 squares, but do threaten the 20 squares surrounding them. So if \$•\$ is where you are and \$○\$ is a square you threaten,

\begin{array}{c c|c c} { \text{Without reach weapon:} \\ \begin{array}{c|c} ○ & ○ & ○ & ○ & ○ \\ \hline ○ & • & • & • & ○ \\ \hline ○ & • & • & • & ○ \\ \hline ○ & • & • & • & ○ \\ \hline ○ & ○ & ○ & ○ & ○ \\ \end{array} \\ } & \quad & \quad& { \text{With reach weapon:} \\ \begin{array}{c|c} ○ & ○ & ○ & ○ & ○ & ○ & ○ \\ \hline ○ & & & & & & ○ \\ \hline ○ & & • & • & • & & ○ \\ \hline ○ & & • & • & • & & ○ \\ \hline ○ & & • & • & • & & ○ \\ \hline ○ & & & & & & ○ \\ \hline ○ & ○ & ○ & ○ & ○ & ○ & ○ \\ \end{array} } \end{array}

Creatures do not need reach to strike you; in fact, these same diagrams work for them. If they stand on a \$○\$ then they can reach one of the \$•\$ squares, i.e. they can reach you (use the grid that corresponds to whether or not they have a reach weapon; your weapon is irrelevant to their reach). However, since your space is larger, they can actually stand closer to you with a reach weapon and still strike you.

This is all kind of weird and very abstract, but Pathfinder is a pretty abstract game in a lot of ways. This simplification is really just an expansion of the already-quite-abstract grid system where a typical person is said to “take up” a 5-ft. cube (I doubt anyone in the history of Homo sapiens has ever actually been 5 feet broad or wide). Basically, you take up that space because you are constantly moving and this is the area you “control” and can therefore move freely in (read: not require an action, not provoke an attack of opportunity). With a mount, which controls its own space, you are able to move around freely atop the mount and so take advantage of the control over that space that it provides.

But that Pathfinder implements an abstraction does not have to be the end of the story. As HeyICanChan points out, Paizo creative director James Jacobs does not consider the abstractions around mounted combat in general to truly be sufficient, suggesting that

Mounted combat is underdetailed in Pathfinder. So, the more you get into it, the more you're going to have to house rule.

In short, Paizo chose simpler, quicker-to-learn, quicker-to-run abstractions for mounted combat, quite possibly because they were focused on more typical cases and didn’t want to bog the system down with special rules for scenarios that may very well not come up in the majority of games (since most riders are just one size category smaller than their mount and therefore the abstraction doesn’t really look too weird). You can choose to do differently, especially if your game isn’t going to look like “most” Pathfinder games and smaller creatures riding very big ones is going to be an important part of it.

But be aware that abstractions are powerful and useful, and reducing abstraction thresholds means greater costs in time to learn, time to run, and complexity. Paizo didn’t think those costs were worth it, at least for their idea of “most” Pathfinder games. You might think they are worth it, at least for your game. But don’t ignore the fact that, worth it or not, the costs are still there. You need to think about them while designing any houserule you want to implement.

Answer 2

Although the circumstances usually involve a reach weapon-wielding rider that's astride a Large mount, fans debate this regularly like in 2011, 2013, 2015, and 2017, yet Paizo has, to my knowledge, never issued any official word.

To sum up, mounted combat does, indeed, say, "For simplicity, assume that you share your mount’s space during combat," but what share means here isn't entirely clear, and no examples are provided. When big and little creatures that are fighting each other share a space, the rules here, for example, cover that eventuality, but the rules don't explain what it means to have the rider share the mount's space.

This fine answer does an excellent job of presenting the traditional conclusion most readers reach. However, this reader would like to offer an alternative approach.

When mounted combat says, "For simplicity, assume that you share your mount’s space during combat," it may mean that a rider shares the entirety of the mount's space, and that would mean all of the squares the mount occupies rather than just its edges. Thus, using this approach, a rider armed with a reach weapon astride a Huge mount threatens using the following diagram:

\begin{array}{c|c} ○ & ○ & ○ & ○ & ○ & ○ & ○ \\ \hline ○ & ○ & ○ & ○ & ○ & ○ & ○ \\ \hline ○ & ○ & • & • & • & ○ & ○ \\ \hline ○ & ○ & • & • & • & ○ & ○ \\ \hline ○ & ○ & • & • & • & ○ & ○ \\ \hline ○ & ○ & ○ & ○ & ○ & ○ & ○ \\ \hline ○ & ○ & ○ & ○ & ○ & ○ & ○ \\ \end{array}

Key: • the Huge mount's space and the squares a rider shares with the Huge mount; ○ the squares that are threatened by a rider that's wielding a reach weapon using this ruling.

This would see the rider threaten 10 ft. from the squares surrounding the mount's central square, and also see the rider threaten the squares 5 ft. around the mount as the rider shares with the mount that dead center square, too.

As previously noted, Pathfinder has been less than forthcoming with clarifications about mounted combat, but this approach does jibe with the ruling put forth by a co-designer of the game on which Pathfinder's is based. Whether or not that ruling's provenance matters—especially as there is no official Pathfinder ruling—is something for an individual group to decide.

Anyway, Pathfinder mounted combat is kind of a mess, and the designers know it: "Mounted combat is underdetailed in Pathfinder," says Pathfinder creative director James Jacobs here. "So, the more you get into it, the more you're going to have to house rule." And, with that in mind, this reader recommends a few mock engagements using both that other answer's approach and this answer's approach, then picking which is preferred. Further, even if the table already agrees that one approach is better, this reader strongly recommends a few mounted combat test runs anyway to get everyone on the same page before trying to incorporate mounted battles into the campaign. The mounted combat rules are vague and complicated, and everyone may have a different opinion on how those rules work.

Answer 3

I think that the RAW simplification only works for mounts that are 1 size larger than the rider I would say that riding larger mounts would invoke the rule.

"If you attempt to ride a creature that is ill suited as a mount, you take a –5 penalty on your Ride checks."

A huge mount eg an elephant is better simulated using existing pathfinder vehicle rules. IRL huge creatures like elephants where fought with a crew and a separate driver normally with a howdah attached - though some times without eg driver and two spearmen / archers (some modern day guerrillas still use elephants but more as transport ie as an APC and not a MICV)

I would suggest using the vehicle rules with a 5x5 platform for up to 4 medium characters to fight from and they would need to use reach or missile weapons. Opponents would also need reach weapons – quite how you handle the driving aspect have a PC to do it or hire a NPC is up to you.

You would also have to be firm with gun using characters "no you can’t have a 4 bore stopping rifle"

The pathfinder supplement Belkzen, Hold of the Orc Hordes does have rules for a Howdah. And a google search finds one or two homebrew rules for war elephants which could be adapted.