House Rule: Siege EnginesJuly 12, 2011
Recently, my adventuring party posed me with a problem: they wanted to kill a dragon using siege engines set in ambush. This would be all well and good, except, I didn’t have any rules for siege engines on-hand, they’re too complex to improvise, and I don’t have any personal knowledge of siege engines outside of Medieval II: Total War. Luckily, siege engines are so expensive and they were running on borrowed money, that I felt perfectly fine saying “the gnolls aren’t willing to cover siege engines on your tab”. However, I’m not one to ever get burned by a lack of preparation twice, so today I dedicate my blog post to the creation of siege engines.
As always, feel free to skip reading and go right to the finished rules PDF: [Link]
Researching siege engines was fun. I knew the basic varieties I wanted–rams, siege towers, catapults, and ballistas (even though ballistas were a fairly rare variety of siege engine in real life, a Roman creation, they’re too much a part of Dungeons and Dragons‘ style to not be included). But I didn’t know much else about them.
The first thing I found out is that siege engines were almost always built on-site, using local materials, and therefore cost nothing but time and the cost of rope–oops, there goes my “the gnolls raen’t willing to cover siege engines” argument. I struggled with coming up with some sort of clever rule in my write-up which said that siege engines don’t cost anything if built on site near a forest, or something like that. But eventually I realized that I was going about this the hard way: I instead went into my old Craft rules, and edited them so that if you are in an area with abundant resources, you don’t have to pay for that resource (like trees for log cabins, or, in this case, siege engines).
The actual statistics for the siege engines were a little tougher to come up with. Not only am I not a fan of the vehicle rules and formatting from the Adventurer’s Vault, but I’m a huge BattleTech fan; my standards for vehicle combat are fairly high. By tweaking the magic item stat blocks, cutting out most of the text of the vehicle stat blocks and throwing it into the description of siege weapons (if all siege weapons are creature drawn and use the same weapon rules, do I really need to repeat myself four times?), I streamlined the formatting. I added some rules for converting Large creatures like horses to Medium creatures like humans, and added some special rules to each siege engine to make each one unique–catapults have a minimum range but can make indirect attacks (which makes them benefit from spotters), siege towers make interesting mobile weapon platforms, battering rams properly provide cover and, while they can’t attack creatures, they do have the ability to severely boost a creature’s Strength check to burst doors and walls, and finally ballistas can attack multiple creatures at once in a line, like the old lightning bolt spell.
It’s not necessarily as advanced or complex as a BattleTech game, but not only are these siege weapons more or less realistic and effective, they’re interesting enough to not be, well, boring.
The final step was price. How much does a siege weapon cost? Well, in ye olden dayes, nothing: siege weapons were built, fought in battles, and quickly scrapped for firewood (whether they survived or not). Nobody bought them, nobody sold them. But, my Craft rules roughly determine how long it takes to build a siege engine by their gp value. Some research turned up some vague results on how quickly college students could build full-sized catapults, and I have my own knowledge of how complex it really is to build a battering ram or a tower not meant to last more than a few hours (at most). In the end, I gave up that research project, as so few people had clear numbers on how complex and long-winded a task it is to build a siege engine, and went with the prices found in the 3.5 Dungeon Master’s Guide. They’re actually much smaller than the prices I would’ve given, meaning the siege engines can be churned out much faster than I expect they could in real life. However, this just makes it better for adventuring and epic battles, and that’s what it’s about, right?
Anyway. The final result is here: [Link]
Maybe not the most comprehensive or awe-inspiring set of rules for Dungeons and Dragons 4th Edition, but they’re simple, effective, and allow for players a few more options when they’re trying to be badass. If I had these a few weeks ago, my players would have had a very different fight with that red dragon–very likely involving siege weapons bursting into flames, possibly with the party underestimating how many gnolls they needed to win and therefore losing. And though the future of that campaign seems bleak, if it ever got to the castle siege stage that I had hoped to get to, these rules would’ve come in handy.
And, I’m sure they’ll come in handy for someone else out there, someday. Need a ballista? I got rules for that.