Chase in DnD

[Frostmarrow]

In the Core Rules of DnD there are no clear cut rules of how to determine the outcome of a chase. I know that there are full rules for chases in different d20 products, such as Spycraft from AEG but those rules are not readily available to all DnD-players.

In the games I play, one situation seem to crop up a lot. The last of the opposition decides to flee the field when the battle turns against them. And we usually like to give chase in order to get information from them or simply to hack them down. Also, sometimes it's vital to know whether a PC manages to escape the city-watch.

I will present my rules for chase below but I would like you to either approve of the rules or disapprove. I'm sure you are teeming with ideas yourself, and of course I'd like to hear suggestions on how to improve the rules, but most importantly I'd like to know if you see these rules as appropriate.

Chase Rules

When a character leaves combat by taking a full move with the intent to avoid the combat, i.e. not drawing an attack of opportunity, any other characters may decide to give chase. When a chase has been established the prey and the hunter rolls dice. The hunter rolls 1d20 and adds his Speed and Strength modifier. The prey rolls 1d20 and adds Speed and Dexterity modifier. If the hunter's result is equal to or greater than the prey's result the hunter has caught up with the prey. Otherwise the prey has been able to further the distance between the hunter and himself.

Modifiers to the chase check:

* Hunters add their Strength modifier to the check.
* Prey add their Dexterity modifier to the check. (This represents the prey trying to avoid being caught by zigzagging or knocking over terrain to obstruct the hunter.)
* For each space (5') by which the prey has a head-start the prey may add +5 to the roll.
* A ranger may apply his Favored Enemy bonus if it applies to his hunter or prey.
* Chasers under the influence of the Haste-spell increase their Speed by 1/3. (15' becomes 20', 30' becomes 40'.)

Results

In either case both the prey and the hunters move double the prey's Speed in feet. If the hunter starts out next to the prey -he will end up next to the prey. Even if the hunters have a lower Speed than the prey they will move the prey's full distance. (Since they can cut corners.) Both hunters and prey are running at the top of their ability but chasing does not count as a run move since the prey is twisting and turning in order to escape. Chasing is considered a full round action.

If the prey beats the chase check of all hunters (if there are more than one) the prey may move an accumulative extra space (5'). This is farther than he normally can travel but he is, after all, running for his life.

Hunters that beat the prey's chase result may move to a space next to and behind the prey and may also refocus. At the start of their next round they can attack the prey normally. The prey can still try to escape if he survives the attack.

Example: A lion moves silently up to a light riding horse. The horse fails to hear the lion so the lion executes a partial charge and attacks the horse. Even with the ability to pounce it's prey the lion fails to bring it down.

The horse wins the initative and decides to run away. Fleeing (i.e. making a double move away from your attacker) doesn't provoke an attack of opportunity so the horse is free to do so at no risk. The horse has a speed of 60' and a dex modifier of +1 so the horse will roll 1d20+61. The lion decides to try to catch the fleeing prey. A lion has a speed of 40' and a Strength modifier of +5 and will therefore roll 1d20+45. Math is not my strong suit but I think this means the lion has a 2.5% chance of beating the horse.

Now, the horse will decide on a point 120' away to move to. (I.e plot a course over 24 spaces.) If the lion's chase result is equal to or greater than the horse's, it will move up to a space directly behind the horse and may add +20 to his intiative order. If the the lion fails (1) the horse will first move 120', (2) then the lion will move up to directly behind the horse and (3) lastly the horse will move 5 extra feet. In the next round the horse will roll 1d20+66 and the lion will roll 1d20+45. The chance of catching the horse is now gone so the lion may just aswell give up pursuit. If the lion still persists the horse will gain yet another space and can add +10 head-start bonus to the roll., and so on.

A cheetah is faster than a lion; speed 50' but is not quite as strong. A cheetah will roll 1d20+50 (speed) + 3 (Strength). A cheetah in the same situation as the lion above will have a 5% chance of catching the horse in flight. On the other hand a cheetah is not quite as skilled at hiding and silent movement as the lion. I guess both animals are eqally skilled at catching prey.
Note that the cheetah can't use it's sprint ability when chasing since a chasing creaure is not "running" per se. Sprinting does allow a cheetah to skip the hiding and sneaking parts of the hunt, though.

There are no anteloops or deer in the Monster Manual so that is why a chose a horse to be the prey. I'm no wild life expert but it seems right to me that a lone lion will be able to catch a very fast animal such as a horse about once in 40 tries. If the sneaking and pouncing is successful though the horse won't stand a chance.

[Edit: The chase rules are updated below.]

 

[Kyramus]

chase rules= running

from the SRD
Run [Full][AoO: Yes]

The combatant can move up to four times the combatant's base speed in a straight line (or three times base speed if the combatant is in heavy armor). The combatant loses any Dexterity bonus to AC since the combatant can't avoid attacks.

A combatant can run for a number of rounds equal to the combatant's Constitution score, but after that, the combatant must succeed at a Constitution check (DC 10) to continue running. The combatant must check again each round in which the combatant continues to run, and the DC of this check increases by 1 for each check a combatant has made. When a combatant fails this check, the combatant must stop running. A combatant who has run to the limit must rest for 1 minute (10 rounds) before running again. During a rest period, the combatant can move no faster than a normal move.

 

[SylverFlame]

Kyramus has the easier applied rules, but I like the cat and mouse aspect of Frostmarrow's "roll rules". Makes the chase more exciting and tense. They flow great two.

One question. Any modifiers for obstacles (ie. terrain, boxes, etc.)? Also, what if more than one person is chasing the prey? Wouldn't that limit the preys ability to run? Kind of like a pack of wolves when they've chose the one deer they'll focus on.

 

[Rybaer]

I might suggest that you add in some penalties to the chase rolls based on how badly injured each party is. You'd expect an injured person to have more difficult time escaping. Similarly, a person badly injured in combat would have a tougher time chasing someone who escaped the fight largely unscathed.

Perhaps a -5 to the check for anyone under half max HP and a -10 for being under one-quarter max HP. A relative scale is more appropriate than a finite one in this case.

This would encourage a person to try fleeing earlier in a fight if they suspect they are badly outmatched...which intuitively makes sense.

 

[Frostmarrow]

Kyramus: The chase rules don't replace the rules for running. The difference is that if you are locked into melee the opposition can make an AoO if you run. If you, instead, take a double move you deny the opposition that opportunity.

Once you are 5' (or 10' if the enemy has reach) a head of you pursuers you can still run. If the current terrain allows it. It's often impossible to make run moves in a maze or a market place due to the "straight line" restriction.

Sylver Flame: The rules anticipate some knocking over furniture and obstructing the pursuers path - it's part of the dex-modifier. However, the DM can as always apply +2/-2 modifiers has he sees fit. (You know, "the DM's best friend" from the DMG.)
If you are fleeing through a crowded market place I guess you'd get a +2 circumstance modifier.

If several people chase the same prey they all roll their checks versus the prey's check. But if I'm chasing Kyramus and you intercept him the DM ought to give you a +5 bonus to your check for every space you are closer to a point of interception than he is. (Depends on the terrain, I guess.)

Rybaer: I leave all modifiers apart from those I've mentioned to the DM. If your DM thinks being wounded makes your chances of escape more limited, it's all up to him.

I'm going to try to reword the rules to make them clearer.

 

[Frostmarrow]

Chase Rules (Updated)

Chase Rules

There are two kinds of participants in a chase: hunters and prey. An opposed check determines the outcome of the chase.

1d20 + base speed + Str bonus (for hunter*) or Dex bonus (for prey*).

* Strength is the key ability for an aggressor and dexterity is vital to avoid harm.

Whenever a combatant makes a double move (not a run), the space that the combatant started out in is not considered threatened. However, any opposing combatants can declare a chase. The prey makes a double move. On the hunter's turn the hunter makes a double move too and must get whithin reach (5' for a medium-sized character) or fall out of the chase. The involved parties make opposed checks. If the prey beats the check of all hunters the prey may immediately move 5' extra. If any hunter beats the check of the prey that hunter may immediately execute a melee attack (or do anything that can be done as a melee attack or a melee touch attack, including attempts to disarm, trip, or make a grab to start a grapple). For ties on chase checks, the character with the higher key ability score wins; Strength for the hunter and Dexterity for the prey.

Modifiers:

• For each 5' a hunter is from the prey the hunter suffers a -5 penalty.
• A ranger may add his Favored Enemy bonus if it applies to the opposition regardless whether the ranger is hunter or prey.
• A character under the influence of a haste-spell adds 1/3 of his base speed to his check. I.e. A base speed of 15' grants a +5 bonus to the check.
• The terrain might grant a +2 bonus to the hunter or prey at the DM's discretion. (A crowded market place is in the prey's favor but an open field is advantageous to the hunter.)

Any character can enter a chase as hunter at the end of their turn as a free action.

Chasing is not considered running and as such the participants do not lose their Dexterity bonus to AC and is not restricted to moving in a straight line only. (Yet, any participants in a chase are actually running at the top of their ability but are also zigzagging and feinting in order to catch or avoid being caught.) Tumbling is allowed and so is Attacks of Opportunity.

 

[CCamfield]

I think that being in melee range should not entirely be necessary. You can probably still chase someone from 15' away or further. You might not be able to attack them, but if they are trying to get someplace then it is relevant.

There were some chase scene construction tips in the old DM Design Kit (which I picked up as a PDF). "Hunter" and "Prey" both make rolls; the difference between the results reflects how much the distance is increased or decreased, depending on who won, with the units of distance depending on whether characters are on foot, horseback, or doing a long-distance "chase" through the wilderness. Bonuses potentially given for good tactics (e.g. the person being pursued knocks over a vegetable cart, creating an obstacle for the hunters). Personally, without the opportunity for choices and tactics, I think chases can be pretty dull.

 

[Frostmarrow]

Consider this example:

Green decides to make a double move away from orange. Orange and blue declares to give chase.

All three have base speed 30' and they have no modifiers to their ability scores. They are all wearing light armor. Green carries a shortsword, orange a long sword and blue a longspear.

 

[Frostmarrow]

Green moves first. He moves 12 spaces to the south. Orange follows him. Blue makes a run move (in a straight line).

Blue is not whithin striking distance (10' since he is armed with a spear) so he falls out of the chase.

Orange is still in the chase since he is whithin striking distance (5'). Green and Orange take opposed chase checks.

Green rolls 5 + 30 (base speed) + 0 (Dex bonus) = 35
Orange rolls 12 + 30 (base speed) + 0 (Str bonus) = 42

Orange wins and can therefore make an immediate melee attack. His longsword strikes true but Green is tougher than he looks and is still standing.

 

[Frostmarrow]

In the following round Green still wants to get away so he makes a double move around a table and heads north as fast as he possibly can.

Orange and Blue declare to give chase. Orange moves whithin in reach of Green. Blue moves whithin 10' of Green and is still considered in the chase for this round since he is armed whith a longspear.

Green rolls 17 + 30 (base speed) + 0 (Dex bonus) = 47
Orange rolls 15 + 30 (base speed) + 0 (Dex bonus) = 45
Blue rolls 19 + 30 (base speed) -35 (Distance to prey when the chase was declared) + 0 (Str bonus) = 24

The prey wins the check versus all hunters and may therefore move 5' free.