User:IGTN/Feral Libram/Size Matters

Size Matters
So, the size rules are, like the rest of the game, broken. This doesn't exactly come as a surprise to anyone. The most glaring flaw is that big creatures have to have enormous strength scores to be as strong as they're supposed to be, which breaks everything when different ability scores are supposed to be comparable and other ability scores don't scale as rapidly. In anything where size comes into play (fighting over a door, or trying to trip someone), a giant already gets size bonuses over a human, they don't need to mess with their stats, too. These strength bonuses also make weird things happen with two-handed weapons, which get an enormous advantage in the hands of giants to the point where a giant would have to be deliberately hindering itself to use anything else.

So, we're revising the way size works here. This will tie in with the carrying capacity revision in Chapter 9. Ideally, this would be modular enough that this can be pulled out to have another reworking of size plugged in here and all you'd have to do is recalculate all stats ever. It's not going to be quite that simple to switch systems, but needless complexity will be avoided.

Before we begin, let's lay out an understanding of what size means. Creatures at different scales behave differently. A tiny brownie can jump and roll out of the way of a death beam no problem. Titans only do that in myths to explain oddly-shaped lakes. What this means in practical terms is that creatures fill up more of their space at larger size than they do at smaller size unless they're standing in pike thicket formations or something like that. What it also means is that big creatures have a harder time dodging things and it's easier to aim at them. Since the relative ease of hitting something depends pretty much entirely on relative size, this will be modeled with a bonus or penalty to the attacker. Also, little weapons are like tiny pinpricks to big creatures, while big weapons utterly smash little creatures. This will be a damage bonus or penalty for size difference. This replaces the usual weapon scaling rules, and also the strength gain for going bigger or smaller. All weapons use the damage die they get at medium size.

The next thing we want is to reduce the enormous gain of power that a size increase gives. Under the current rules, a size increase is an enormous gain in power for any strength-based character, a nerf for a stealth-based character, and neutral with maybe a slight power gain if you play your cards right for a casting character (AC penalty, but it comes with a natural armor bonus and Con bonus by the monster manual rules). Since players can, for the most part, control whether their character uses the MM size change rules, in practice that means that size increases are an enormous unmitigated power increase to characters that need them, making playing a medium-size fighting character who has the option to grow bigger a clearly inferior option. Since we like our stalwart heroes facing off against monsters several times their size, this has got to go.

An added benefit of this is that it lets us have low-level heroes fight big creatures. While creatures on a truly epic scale should be saved, in most cases, for adventurers with a similar scale of accomplishments, there's no reason to make, say, giants or ogres nearly as powerful as they are. Really. Large and maybe even huge creatures should be viable enemies from the start of a campaign, and a medium strength-based opponent should remain viable all the way to 20.

Big Monsters Need Big Rules
Having discussed these matters at length, we can now develop a rules system for them. Note that using this rules system will require conversions of creatures in the monster manual. Selected conversions will be given in an appendix. When a creature attacks a creature of a different size category, it gains a bonus or penalty to hit depending on the size difference. A creature one size category larger than its target takes a -1 penalty to hit; one category smaller, a +1 bonus. For each additional size category smaller it is, it gains a +2 bonus to hit; for each size category bigger, it takes a -2 penalty. Larger creatures, however, do more damage when they hit, gaining a +5 bonus to damage, a whopping +10 more for each size category larger beyond the first. Smaller creatures merely take a -3 damage penalty, -5 more for each size category smaller beyond the first. Unlike other damage penalties, this can reduce damage to zero (but not below).

These bonuses look huge, but compared to what they were doing before, they actually amount to a nerf. A greatsword-wielder, for instance, taking the Large Size feat, gains a net +3 to hit from the strength increase and +9.5 damage (+6 from strength, +3.5 from the extra die). Huge Size does the same thing again. Just converting the attack bonus the old Large Size granted to the penalties we're using now is worth a +10 damage bonus, and we're stripping away the whole thing where big monsters have big strength scores just because they're big.

Since we want it to be possible to get underfoot, wrestle with things bigger than you, and all that, we're changing the size modifier to special attacks to a flat +4 per size category difference in favor of the bigger creature. This applies to the Lift and Hold Down grapple options, bull rush, and so on. Since getting underfoot is such an important part of all of this, this applies to trip attacks only if the attacker does not have the edge.

Size and Precision Damage
Precision damage (like sneak attack) only works when you can deal damage without it. You don't need to actually roll your damage dice without it, check, and then roll sneak attack; just compare the most you could roll, with all your appropriate modifiers, against the damage penalty for the size difference. The normal rules for dealing precision damage also apply. Otherwise, the attack cannot penetrate deep enough to hit the creature's vitals, and so does not do precision damage.

This rule applies separately to critical hits and non-critical hits. That is, a halfling rogue with a nonmagical battleaxe, strength 10, and no other modifiers (size small, max damage 8) deals no damage to a large creature, and so cannot sneak attack it, except on a critical hit (maximum damage 24), where it can damage, and so sneak attack, a creature five size categories above it (anything up to Colossal).

Power attack can likewise affect your ability to do precision damage, by increasing your maximum damage. By using power attack, said halfling can, on a non-critical hit, sneak attack a Large creature (+1 BAB), Huge creature (+3 BAB), Gargantuan creature (+6 BAB) or even Colossal creature (+8 BAB), so long as they take the requisite penalty to hit.

Size and Space
"obligatory HHGttG quote goes here"

So, the space/reach rules. Except when size differences get really big, these actually work pretty well. Small creatures fill smaller portions of their spaces than big creatures do, which is intentional because small creatures are much more nimble and able to maneuver within their space than big creatures are, even with similar dexterity. This isn't quite good enough for long creatures, which need bigger spaces; we'll get to that on the final table.

This also explains the 5' step rules. Creatures close to medium size take 5' steps even when they're much larger because they're much less mobile, relative to their size, than medium creatures are. Really large creatures make larger adjustments. These will be given on the final table.

Really tall things do occupy bigger spaces while prone, though, since they're flat against the ground. Prone tall creatures occupy the same space as a long creature of their size. We're bringing back the tall/long space difference that 3e had, but only applying it to creatures bigger than large size. This is because medium and smaller creatures, because of their relative nimbleness, tactically control their space; larger creatures physically occupy much more of it.

The Foot-Grinder
It's possible to slowly grind a really tall creature down, hacking at its feet until there are no more feet to hack at, stabbing its leg arteries, until it keels over dead. There isn't actually a problem with hacking things apart from the bottom like that; people can die from blood loss from leg injuries, and hacking something's leg to pieces can bring more within reach.

But encircling a giant monster and pounding on it until it dies is kinda anticlimactic. People are supposed to swarm over these things. So we keep the normal rule where a size difference of three steps means you can exist in eachother's space just fine and add that if you're attacking a creature in melee from outside its space, your to-hit bonus for size difference is capped at +3. If you have a reach weapon, you can bypass this cap if you are within your natural reach of it (and it's still in your normal reach on account of it being really big). Ranged weapons ignore this completely.

Also, people want to have cinematic fights where they climb on top of monsters and hack at them from there. This is an awkward angle for the monster to hit from, so the damage bonus the monster gets for being big is halved if it's attacking you while you're aboard (to +3, +5 per size category beyond the first, the same as the penalty you were getting). Likewise, the damage penalty you get for being small is halved (to -1, -3 per size category beyond the first). This makes having a large size differential and power attacking away your attack bonus into a winning strategy. Go nuts.

Giant Hammers
Big monsters also have big attacks. When a big creature makes a melee attack, it can target a space the size of a tall creature two sizes smaller than it and attack every creature in that space, using the same attack roll. This doesn't apply when its attacking into its own space, though, and doesn't apply to special combat maneuvers like tripping, lifting, and so on, only to attacks made for damage. Nor does this apply to attacks of opportunity.

If you're really big compared to your target, four sizes or more larger, you can fling them away from you with an attack, making a free bull rush attempt for which you do not need to move with each attack. If you apply this to an area attack, you must attempt to push every creature in the area, using the same bull rush roll. If you hit multiple creatures, they scatter in a random direction (left or right) of the distance they're launched, up to half the length of the bull rush.

Giant Steps
Since we don't want melees to degenerate into set-position battles where a big thing gets surrounded by a bunch of little things and worn down until it dies, we want to make these battles more mobile. So here are a few rules to do that.

Big monsters, while their inherent mobility is a lot less than yours, are also really hard to stop. If you're at least three size categories larger than someone, you don't provoke attacks of opportunity from them for moving. Also, you can make free unarmed attacks while you move, again without provoking an attack of opportunity. These are area attacks that affect an area equal to the area of your normal melee attack (as above), and you get one for free every time you use land or climb movement to move a distance equal to half your space. You can spend that much movement to make one in place, too. This must be directed into your space (an exception to the general rule that area attacks cannot be directed into your space). This attack does lethal damage if you have claws, scales, or shoes on your feet. The only defensive advantages they get are, first, that if their space does not entirely overlap your movement, you take a -4 penalty to hit, and second, that they can set weapons against a charge and get the full benefit against this attack even though you aren't charging them. Plus, if you're damaged by an attack made by someone as you step on them, it counts as a Caltrop.