Caltrops and the Battle of Celduin Crossing

[Celebril]

I went ahead and let my players invent caltrops in Middle Earth. So now I am stuck with how to account for them in the game mechanics. Historically caltrops were used to breakup charges. Soldiers couldn't charge if they had to watch where they stepped and animals were the real focus of caltrops, because they would be maimed if they stepped on them. What is lucky for me, as the LM, is that the Fellowship only strew them across the bridge. So I don't have deal with caltrops littering the landscape. So back to my question, how do I account for caltrops used against orcs? Also, how would caltrops meant for orcs affect a troll? I was thinking that orcs would be counted as weary until they are either pushed the caltrops to the side of the bridge or over the bridge. This would simulate orcs trying to pick their way through the caltrops. As for the hill troll I would think it would pretty much ignore them. Any thoughts here would be greatly appreciated and welcomed.

[Otaku-sempai]

Historically, the use of caltrops can be traced to at least the time of Alexander the Great, so it's not unreasonable to think that someone in Middle-earth invented them earlier. We could postulate that they might have been first conceived in Umbar as a defense against the soft feet of the Mûmakil (and camels?) of the Haradrim. Without working out in detail how caltrops might be used in TOR, here is how they are presented in D&D 5e:

Caltrops. As an action, you can spread a single bag of caltrops to cover a 5-foot-square area. Any creature that enters the area must succeed on a DC 15 Dexterity saving throw or stop moving and take 1 piercing damage. Until the creature regains at least 1 hit point, its walking speed is reduced by 10 feet. A creature moving through the area at half speed doesn’t need to make the saving throw.

[Falenthal]

You can make the orcs Weary until some of them succeed at an extended test of Vocation (Craft) of 4 successes (or whatever number you see fit) to clear the path for the rest.

The troll might lose a few dice of Endurance (2d6), but otherwise run over the caltrops ignoring them.

If you want something more detailed, ask the players how many of them collaborate during the preparations spreading the caltrops. Make them roll Craft or Battle. Add all their successes. That's the number of dice the Troll rolls for his damage, and the number of successes the orcs need to clear the zone.

[Indur Dawndeath]

I would use the mechanics already in play.
Add bonus battle dice equal to the number of successes on a skill test for preparation of the battle of Celduin.
Later ask the players to spend a fellowship phase to create a number of caltrops for the next adventure phase, adding perhaps one additional battle dice on each battle.
I would not make the effect better than other preparations for battle unless they spend either treasure or fellowship phases, maybe even both...
The same way that players are not getting bonuses for camouflage and soft boots when sneaking. It is assumed that players are doing what they can already.

If no additional time or effort is spend, then just let the players narate why the normal battle dice are due to intelligent use of caltrops.

[Otaku-sempai]

You can make the orcs Weary until some of them succeed at an extended test of Vocation (Craft) of 4 successes (or whatever number you see fit) to clear the path for the rest.

The troll might lose a few dice of Endurance (2d6), but otherwise run over the caltrops ignoring them.

So maybe:

Caltrops. As an action, you can spread a single bag of caltrops to cover a 5-foot-square area. Any creature that enters the area must succeed on a Movement test (Athletics) at TN 14 or stop moving and lose 1 point of Endurance. Until the creature regains at least 1 Endurance, its walking speed is reduced by 10 feet. A creature moving through the area at half speed does not need to make the check.

[Halbarad]

Caltrops were primarily used to slow the approach of an enemy. I'd suggest that the use of Caltrops might extend Opening Volley numbers to 2-4 or 3-5 instead of the normal 1-3.

[Mytholder]

I would use the mechanics already in play.

Seconded. I'd be really hesitant to add new mechanics when you can just treat them as Battle dice and resolve everything through description.

[Celebril]

Thanks everyone for the great suggestions. I have a lot to think about. I am probably not going to use the existing mechanics because I am pretty sure my players will feel cheated if all they get out of their ingenuity was extra dice. They are already been through six Fellowship Phases so they don't really need the extra dice. I need to give them something I can make cinematic as well as functional. I love the idea of extended open volleys.

<spoiler alert>

I have to also take into account that the orcs already know what has been happening because the Master attempted to bargain with the orcs and inadvertently ratted them out. As soon as the Master made his "I am the Master of this Town" pitch the players went "f' you" and turned to the villagers instead. So the Master secretly sent one of his sons to negotiate with the orcs which the players will find out didn't go so well for him.

[SpottedBill]

Try to validate the players' ingenuity through the narrative, not the mechanics. If you're going to come up with new rules for every little thing your players come up with, your players will think they can "beat" the rules. That kind of thinking is from a "GM vs. Player" line of thought that was popular in RPG's at some point.

If it's narratively appropriate, tell the players how the enemy is stuck on a bridge under a rain of arrows, make it feel like they've won time with their idea. Maybe it buys them more time to prepare for an unexpected element of the battle?

Mechanically, you could have the caltrops help with ambushing the enemy. They might give them one automatic success on the preliminary Battle roll or the Ambush task roll. The enemy is stuck on the bridge, so you could give the PC's extra opening volleys before the enemy gets through the bridge. Perhaps remove a couple cannon-fodder Adversaries before the close combat begins as they're still squirming in pain on the bridge.

[Rich H]

I would use the mechanics already in play.

Seconded. I'd be really hesitant to add new mechanics when you can just treat them as Battle dice and resolve everything through description.

That's how I'd roll too (deliberate pun, thanks). I give my players extra bonus dice during a battle when they come up with particularly innovative ideas for a battle as well as those gained as part of their Preliminary Rolls. It's a really elegant way of doing things that the system already accommodates beautifully.