Large creatures can be a let down in many an Oldschool RPG fight. I recall one player saying “Gee, I though ogres would be tougher” after the party slew a pair of them in 2 rounds. I’ve seen a big beast brought down before it could do much of anything in many game systems even those that seem to account for size in the game mechanics ( I recall a giant being slain by a party of 3 or 4 150 pt characters in GURPS before it could get into position to take a single blow).
Large creatures often lose quickly because they are outclassed by the attacks of multiple opponents at range. Without deploying special attacks methods such as dragonbreath the big guys are often at a decided disadvantage in ranged combat; it should work out that way that’s one reason humans dominate the planet in real life. How can we improve the odds or make the fights more exciting?
Have combat options open to all large creatures that are quick and easy to resolve under the rules:
The Trample, large creatures can attack multiple foes simply by trampling them. The creature overruns a position of smaller foes by charging through them. Everyone in the path must make a saving throw or take damage from being trampled. I recommend a simple 1d6 of damage for every 4 HD the trampling creature has. A simply large creature continues on its path until 3 foes make a save (at any point in it;s path), a huge creature continues on it’s path until 4 consecutive foes make a save or it suffers damage over it’s HitDice/Level from opportunity attacks (spear set vs. charge) or incidental damage.
The Pin, a large creature can can simply pin down a smaller foe. This require a successful attack on the large creatures part against a single smaller foe with a penalty of -2 to hit to reflect greater percussion being needed. The foe get’s a saving throw to break free at the end of this round and each following round, anything the foe is carrying in hand is dropped. This pin attack will do normal damage this round. On successive rounds the creature will be able to automatically hit with it’s primary attack against the pinned foe and get a bonus of +4 with other attacks it may be able to employ if not begin attacked by allies of the smaller foe. A pinned foe can choose to try to attack (ay -4) or try to escape (at the end f the round).
The Grab, large creature can grab smaller foes either in their mouthes or claws if they are built for it. A grab attack is made at a penalty of -4 and if it hits the smaller foe can make a saving throw to break free at the end of this and following rounds. A grabbed foe may be carried away and will suffer an automatic hit from the bite (or claw) attack each round even if the large creature is begin attacked by allies of the smaller foe. A smaller foe grabbed by a larger creature may either attempt to attack the larger creature or break free in normal initiative order. Depending on size and strength the larger creature may be able to move away with the grabbed victim at up to running rates, when running like this the smaller foe suffers no damage from the grab attack.
The Drop, this goes along with the grab at any point the large creature can drop the smaller foe who suffers appropriate falling damage. this will clerkly have more impact the bigger the creature or if they have the power of flight. Anyone dropped will land prone unless they are appropriately nimble and make a save.
The Toss, this goes along with the grab, on any round following the grab the large creature can toss the smaller foe away. A successful hit roll vs an unarmored target is required and the smaller foe can be thrown 10’ per 2 HD the creature has and suffer 1d6 peer 10’ thrown as if falling (a save is allowed for nimble foes to cut the damage in 1/2), if there is a barrier in the way damage is still suffered and no save is allowed. If that hit roll fails the smaller foe is dropped but only suffers 1/2 damage normally accounted for in the distance dropped from the larger creatures grasp.
The Punt, a large creature may simply knock a smaller foe away. This happens on a normal attacks made at -2 to hit if the creature is focusing on it or on any attack that does damage equal to or less then the Strength score of the smaller target. A foe that is punted away is thrown 10’ per 2HD and lands prone, a save is required to avoid being stunned by the impact.
The Shield Smash, a large foe can crusha shield meant to block attacks from man-sized opponents (which means all normal shields). Any successful claw,slam, or similar attack on an odd #’d attack roll that hits a shield using smaller foe will damage the shield. If you have no fancy shield rules or equipment damage it’s broken on a failed save (your rules could have a smashing blow save for equipment, don’t forget them).
The Crush, if a large creature is big enough it can simply crush a smaller foe with it’s mass. A crush attack is made at -2 to hit and the smaller foe gets a save, if the save fails the smaller foes is knocked prone and suffers 1d6+1d6 per 3HD the large creature has. The large creature loses all further actions (and stops moving of course) and has to make a save itself to avoid being considered prone until it can act next round. The smaller creature crushed flat under the larger creature is prone under the larger creature and is helpless until the large creature moves and also suffers 1/2 damage of the original crushing attack on each round it fails a save. A nimble warrior is allowed to attempt to attack a creature trying to crush it, they will automatically lose the save vs crush and be trapped helpless under the larger creature but may strike as if setting vs a charge if their weapon would so allow at the same time (the nimbleness can be determined by Dexterity, initiative or declared actions as appropriate).
Unimpeded Movement, large creatures can just ignore smaller foes now and again, a bull can wade through a crowd of men: surely a 40' tall giant or 100' long dragon just isn't going to care if a person is in standing in the way if they aren't much of a threat. If a creature is much larger it can simply ignore smaller foes when moving (a bunch of mice or ants might be icky but they really can't stop you from walking through them). Anyone who tries to block the large creatures travel runs the risk of being trampled when they could otherwise dodge aside with no save required if the large creature isn't tryign to trample the smaller foes intentionally. A DM should use this with discretion but seriously, unless the PCs are superheroes they are not standing in the way of Godzilla are they?
All of the above attacks should be allowed to all larger creatures able to physically attempt them. Don’t forget large creatures can charge and this can decrease the number of ranged attacks they will face.
Other options are in increase the defensive options of larger creatures, all of these may not apply to all creatures and some are slight alternatives to each other that may apply to different large creatures but not all.
Man-sized Weapon not designed to fight large creatures, it’s a simple fact almost all weapons are designed to fight other man-sized foes not large creatures. When a man-sized foe is using a weapon not specifically designed to attack larger creatures the weapon only inflicts 1/2 damage. Basically if it’s not a spear, and atl-atl javelin, or an arrow used in close range it is only going to do 1/2 damage vs a large creature. Axes might work great against giants but not be all that meaningful vs a triceratops or island sized dragon turtle. Use with discretion a derringer pistol isn’t designed to shoot elephants for example but a burst from an SMG isn’t going to be pretty.
Weapon Loss and Breakage, as above: most weapons are not meant to endure the stress they would take striking a large foe. Any bad miss or good hit has a chance of ruining the weapon in hand or simply getting it knocked away. Any miss in melee that is under the large creatures HD could end up with the weapon knocked out of the hands of the smaller attacker a saving throw will allow the attacker to retain the weapon. Any successful hit has a 2 in 6 chance of damaging the weapon (in absence of fancy damage rules in your game if a save fails the weapon suffers a -1 penalty each time it’s damaged and breaks when this penalty is over 1/2 the weapons damage rating).
Damage Threshold, attacks must cause a specific amount of damage or be ignored. If a large creature has a damage threshold of 4 any attack that causes 3 or less is ignored (or causes 1 point in a camping with a generous DM). This needs to be scaled to the expectation of the campaign and the weaponry on hand.
Achilles Heel, the large creature is only really vulnerable in one location. Attacks from non-magical weapons do only 1 pt if not going for the vulnerable location, magical weapons only do 1/2 damage (if you have critical attacks they either don’t apply unless directed at the special location or indicate the special locate was hit by coincidence, DM’s call).
The attack vs an achilles heel may require a called shot and should likely be limited in how many attacks may be directed against the vulnerable location based on position and weapon used (if using very abstract combat only the first 2 or 3 attacks should be allowed to possibly hit the vulnerable spot). A large creature can be given different Acs for different locations (some creatures in old school rules use this but not many).
Some weapons need not apply, this is a variant on weapon size but some weans just aren’t doing damage to a large creature in any normal combat situation. A club or mace might not be the best choice to use against a dinosaur, hippo or bison. Weapon types can outright be ineffective, minimized to 1 point or 1/2 damage.
This thing is scary, large creatures are frightening to face in combat. Sure everyone wants to think their PC is a bad-ass but not everyone is aware of their limitations until they come face to face with them. PCs shouldn’t lose all nerve when facing a large creature but when facing a large creature with HD in excess of their own Level (or type of large creature) for the first time a save is required to not briefly balk in combat (characters of certain background sand classes may not suffer this effect vs some foes, others may face it their entire career). If someone balks they are considered surprised until the end of the round. NPCs may require a morale check to stay and fight, inspiring leadership and good planning will surely win out over base craven instincts (?).
What about PCs vs small monsters? Well turnabout is fair play when fighting a smaller foe a PC should be allowed to attempt many of the offensive actions as if they were a larger creature. Such methods are primal and could cause the attacker to lose out on actions and special abilities that require more finesse. I’ve had a PC punt giant rats and kobolds, one used a goblin as a club for a little while (they get soft and unwieldy fairly quickly but there is a morale hit when a 6 and a half foot tall warrior starts swinging away at his goblin captors with one of the goblins).