D&D 5E Anti Frost Giant defences?

[FreeTheSlaves]

Okay, so there's a small 10th level party fortifying a motte and bailey fortress against a winter attack of Frost Giants. They've got all Autumn to prepare, a local servant population of about 100, and collectively about 10k gold to spend. Not possible to preemptive attack for whole heap of reasons.

Frost Giant numbers are uncertain but could be 10-20, and they stand like 18' tall. Their leader is smart and also commands some Ogres and Ogrillons.

(Party is already negotiating with a neighbouring Orc tribe to dissuade them joining the giants, a young adult Silver Dragon backing this up.)

Back to the fort, what non-magical defences could they prepare?

 

[WayOfTheFourElements]

A moat filled with [acid, burning, pitch, scorpions, wolverines, etc.]

 

[WayOfTheFourElements]

Better yet, rig the castle to collapse in on itself. Then lure the giants inside and have the castle walls crush them.

 

[Eltab]

Small passages (medium must squeeze, large cannot possibly fit through) to critical areas.
Heated ranged projectiles (just to tick 'em off)
Look up IRL fortifications from about 1600 - the star fort style - and especially the surrounding countryside.
Be prepared with catapults &c to get into a 'rock-throwing contest'.
Be willing to use your own smashed masonry as boulders to throw back.
Critical facilities underground to prevent damage due to flying boulders.
Cut down all the trees within a quarter-mile but let hedges &c grow - you have Cover but the giants do not.
Talk to some giant leader higher up in the Ordning to be your ally / advocate / protector.
Weather magic: it gets hot out when the frost giants arrive.

 

[aco175]

Check out some of the threads on kobolds defending against humans to see their tactics with small tunnels and such. There seems to be a lot of parallels.

 

[MarkB]

Clear the approaches so that there's no cover, then crisscross them with pits, ditches and spikes to make them difficult terrain for Huge creatures. Filling a pit with water during autumn will turn it into a natural pit trap once winter sets in, as it will freeze over and then get concealed with snow.

Buy loads of longbows and arrows, hire some professional archers and/or train up the available servants to fire them. Longbows outrange hurled rocks by 360 feet, which will take the giants 18 rounds to cover at a dash if moving over difficult terrain, and even with disadvantage for long range, 100+ archers can get a lot of hits in during that time.

 

[Eltab]

Mount heavy crossbows on the walls. Build a couple huts at the maximum range, a couple huts at the boundary between Short and Long ranges. Tell the crossbowmen "If you feel lucky you can start firing when the giants pass the outer huts. When they get closer than the inner huts, everybody let 'em have it!

Have a plan to evacuate the civilians when danger arrives; somebody 18 feet tall should be easy to see coming through farm fields (but not via a forest or taking cover inside a substantial town).

Pickets and alarm-ringers (like the mountaintop fire posts in LotR) whose job is to set a warning signal then get out of the way. Untrained peasants can "yell for help" or "call for the cavalry" and it even comes naturally to them.

 

[LordEntrails]

What magic do they have? Shape earth is very useful.

 

[Eltab]

A moat filled with [acid, burning, pitch, scorpions, wolverines, etc.]

Hmm, maybe. I don't think the giants would handle a Swarm of Piranha very well. Or a ditch full of dried brush you will set on fire once they step in it.

 

[Eltab]

BTW, for humor value, the giants' ogre followers have some goblin-chuckers from Storm King's Thunder. A few of the goblins might even be able to run around starting trouble after arrival. (Gives the monk and 2HW barbarian something to do.)