For the ballista, you need several things. The primary 2:
-A strong mobile framework that can be shifted to allow for aiming. A very heavily reinforced small wagon could provide most of that, but without further modification you'd basically be parking it and hoping the dragon moves in front.
-A winching device with enough mechanical advantage to allow you to draw the bowstring back paired with a trigger mechanism that can both hold the string and be released without too much difficulty.
As to a hint on how difficult these two items are for amateurs to manage, badly made ballistaes are known to violently rupture under the strain involved, possibly killing users with flying pieces.
Now, I'm not going to say it isn't possible, it could conceivably be done. But you ought to be cringing at the thought of trying to slap one together with scavenged bits and pieces on short notice and without at least one expert on hand.
Note: Neither of the two designs linked provide anywhere near enough of a mechanical advantage for this sort of thing. One's a toy, the other is a simple crossbow What you need to be looking at would be more like this: Source 9r or this: Source 7f
For Tazskan, yes and no. They can be considered distantly related. Amabalis probably would have some sympathy. But given that the wyverns are highly dangerous critters liable to eat both him and his master, I suspect that sympathy would be muted a bit.
Edited: daishain on 21st Dec, 2017 - 2:15pm
I'd be curious to hear the Queen's response to Velon's further inquiry about the large bow. Is it for killing dragons simply because it is huge, or because of magical properties.
Yes as of right now it seems the priorities would be clear the barracks, investigate the dragon's lair, and then strategize our dragon attack. That latter part could include multiple people carrying the bow down and simply mounting it on a table or something such that the arrow can rest on the table while the string is drawn back by a lever or people heavily exerting themselves with their whole body. Hopefully it could be simply. Daishain brought it up and said it's specifically for killing dragons, so I don't think it should be ignored. In the meantime we can simply keep an eye out for supplies; 'small' could giant table, rope, etc.
Unfortunately the headache of guarding the control room persists. I'm tempted to say we should just let our non-fighter twin friend there guard it with a hut as suggested so we can all get in on the fun. Daishain has given little to no warning of further danger to the room so perhaps we can risk it?
Edit: Ten players and no one made a character who is an expert on siege weapons?! Come on, team! (Yes, completely kidding. Not usually my first thought when creating a Dungeons & Dragons character.).
Edited: Cinder on 21st Dec, 2017 - 2:13pm
Libraries are always good places to go. I am concerned that most of the books might be made for giants in mind. Making Poljen the one most suited to do research, because he can lift the books and read giant. I think that would make his full title "Poljen, son of Nels, Slayer of giants and dragons, Last of the Snow Leopards, the Librarian"
Also Nikolaos can cast levitate once per day without burning a spell slot which may help transporting the ballista.
Edited: Kingowlbear on 21st Dec, 2017 - 2:18pm
I will let others volunteer with the bow. It sounds all kinds of risky and awkward. The people best suited to try to draw the string back are also unfortunately the ones that we can least afford to not have hacking away at the creature. That thing will have all kinds of accuracy issues. Hopefully it wouldn't hit one of our group fighting the dragon. This has comedic potential written all over it.
If you can manage the feat, it would likely be worthwhile, the bow is magic, it deals an extra 2d6 damage to creatures of the dragon type (On top of its base of 3d6), and forces them to make a Con save vs their wings going nonfunctional for a while.
The king's father was known for bringing down hostile dragons with the thing in one or two shots thanks to causing them to fall out of the sky.
Edited: daishain on 21st Dec, 2017 - 2:26pm
If nothing else, and if we can truly take this castle for our own long term, we'll have it in our bag of tricks for the future. One of the party's spell casters could pursue the magical means to enlarge/reduce as needed so someone could use some of those weapons in the right spot. A well made, portable ballista could also be built by a commissioned expert for use down the road.
Sorry Thomas, Velon loved the idea too, but the Dungeon Master just said the closest thing we're probably going to get to "Don't do it". The only other idea I had was to start our fight against the dragon with it for just one shot. The entire party holding either end of the bow (Or wedging it in a doorway) and Velon and Poljen pulling back the string with all of their might. Probably more trouble than it's worth though.
This is when we need a clear consensus. And I think Cinder has it right. We do what we know can be done, and Daishain will let us know if we stumble across the pieces we would need to even attempt building such a contraption. But I would like to point out something. We have the ability to teleport, via a scroll. I bet the bad guys have similar abilities. So they could pop in almost anytime. So let's not spend too much time trying to overthink this.
I really doubt we could build a ballista and move it into the dragon's lair, and be able to use it, without tremendous difficulty. If we fight the dragon there, it is impractical. Making one after we have landed and emptied the castle for defense in the future, hey, that is another story altogether. Something to do between this and the next adventure. For now, let's do a sweep-&-clear.
EDIT: In answer to Lora's question about setting the castle down… if we can find a new spirit to drive it, after we release Escalarotta, then we will once more take it to the skies. Definitely!
Edited: PaulNelson on 21st Dec, 2017 - 2:32pm
Yup, let's keep checking off our To Do's, finishing the clear with emphasis on the barracks and then getting eyes on the dragon and its lair. Can't wait to get to that fight!
Ugh, people have lots of good points about all of the ways the enemy could come back to the castle. I especially hate that they could have a teleportation set up already, as that's more of a surprise attack than anything. Perhaps if we take the castle long term we could pay a high level magic user to ensure the place is rid of all such magics, and is even protected from intruders entering secretly somehow. We'll see!