A super simple way to run Monster Hunter-style "titan fights" in D&D 5e

 

Attacking a sack of hit points until it dies is okay for bandits, orcs, kobolds, and even larger enemies like lions or brown bears. However, it's just not as epic when fighting something towering over you with a head as big as your character's entire body.

Here's how to make Huge and Gargantuan creatures more fun to fight for your players and more fun to run as a DM. As always, I keep these homebrew mechanics super simple so that the whole table can get a grasp on them without too much reading.

Attacking specific parts

The 14-foot-tall balor towers above you, brandishing its lightning sword and its fiery whip. It's your turn in the initiative, and you have several options for where you want to hit it. Your choice affects how much damage you deal and whether you succeed on a hit at all, and some choices may cause "Wounds."

Wound Mechanics

• If a creature gains hit points, it can choose one of its wounds to remove. Heavy Wounds must be removed before Light Wounds.
• Crippling Wounds cannot be removed except by powerful magic like the Regenerate spell.
• A creature removes all Heavy and Light Wounds when it finishes a Long Rest.
• A creature with Legendary Resistance can expend one to negate a Wound before its effect takes place.

Below are a player's options for targeting a creature:

Core

Targeting the chest, torso, or general bulk of the creature is for players who want to keep things simple, trying to hit the creature as reliably as possible and deal damage so they can kill it—basically normal D&D rules. A balor's core has its base AC of 19, and on a hit, the balor takes full damage from the attack.

• Normal AC, normal damage

Arms

Since limbs aren't vital parts of its body, hitting one doesn't do as much damage. However, wounding an arm or hand can change the course of a battle in your favor if it interferes with that enemy's ability to fight. Since you have resistance to fire damage but not lightning damage, you decide to target the balor's arm that's holding the lightning sword. The AC is still 19, and if you hit, it does half damage.

• Normal AC, half damage

Below are the Wounds caused by hitting arms:

1. Light Wound. The creature drops any item it's holding.
2. Heavy Wound.  The creature has Disadvantage on attack rolls made with that arm. If it's holding a shield, that shield only grants a +1 bonus to AC instead of +2.
3. Crippling Wound. The arm is broken, maimed, or severed completely, making it unusable. The creature cannot hold items in that arm or use it to attack with.

Legs

Legs are similar to arms, but their wounds affect the creature's mobility more than its ability to attack. Although, at your discretion as DM, a creature who kicks as its attack could be affected similar to an arm.

• Normal AC, half damage

Legs gain the following Wounds on each hit:

1. Light Wound. The creature falls prone if it is not flying.
2. Heavy Wound. The creature's speed is reduced by half.
3. Crippling Wound. The creature's speed is reduced to 10 feet. If both of its legs have Crippling Wounds, the creature is permanently Prone.

Head

The head is a creature's weak spot, and it knows this, so it keeps it well protected. If you can manage a head shot, you'll do critical damage and cause a head wound, so it's a great high-risk high-reward tactic. However, melee attackers may find it difficult to reach a bipedal Huge or Gargantuan creature's head without grappling it first and climbing up its back—and even a quadrupedal titan may have a limited hitbox depending on which way it's facing relative to the attacker.

• Three-Quarters Cover (+5 AC and Dex saves), critical damage

Head Wounds are as follows:

1. Light Wound. The creature's concentration (if any) breaks, and it loses reactions until the end of its next turn.
2. Heavy Wound. The creature gains a level of Exhaustion.
3. Crippling Wound. The creature is Stunned until the end of its next turn and permanently Blinded.

Wings

If a creature is flying out of reach, you may want to ground it by wounding its wings. Wings act as limbs, but they're a bit harder to hit since they're behind the creature and in constant motion. The balor's wings have Half Cover, so their AC is 21.

• Half Cover (+2 AC and Dex saves), half damage

Wing Wounds cause the following effects:

1. Light Wound. The creature loses 30 feet of height if it is flying.
2. Heavy Wound. The creature falls prone.
3. Crippling Wound. The creature's flying speed is reduced by half, and if it ends its turn in the air, it falls. If both its wings have Crippling Wounds, the creature has no flying speed.

Tail

Some creatures may have tails that pack a powerful punch or have nasty venomous barbs on the end. In these cases, you can focus fire on the tail to hopefully take it out of the fight. Tails are targeted the same as limbs.

• Normal AC, half damage

Below are some tail Wound options:

1. Light Wound. The creature falls prone.
2. Heavy Wound. The creature gains Disadvantage on attacks with the tail, as well as Strength and Dexterity checks.
3. Crippling Wound. The creature cannot use the tail to attack, and it gains Disadvantage on Strength and Dexterity saving throws.

At the DM's discretion, other parts may be targetable, with these options used as templates for AC, damage, and Wound types.

Spells and area effects

Making attack rolls on parts of a creature are fairly simple. However, what about abilities and spells that cause conditions? Well, mental conditions, like Stunned, Blinded, or Deafened , which This might require a little imagination on the DM's part, but think of it basically as the player is focusing the condition to be more extreme on a smaller part of the body.

As an example, imagine a ranger who casts Ensnaring Strike on a fire giant. If the strike hits the giant's core, the normal effect would happen: its entire body would be Restrained by vines. However, if the ranger instead targets the giant's arm, all of the vines that would've restrained the entire body are condensed on one limb. The arm is completely unusable while the condition persists, but the giant doesn't suffer from reduced movement, and creatures only have Advantage on attack rolls on that specific limb.

When it comes to area effects, like a Shatter or Fireball spell, if the core is in the area of effect, the creature takes the damage normally with no Wounds. However, if a spellcaster focuses a spell to only affect a body part besides the core, it receives a wound as normal if it gets hit. Remember that wings have a +2 to Dexterity Saving Throws and heads have a +5.

If you are curious about a specific spell, effect, or situation presented in this ruleset, or if you've tried these mechanics and have feedback, I'd love to hear about them in the comments!