Need Inspiration Creating "Boss Monsters" for a Level 5-9 Campaign!

[wayfare]

My players are currently 4th level and awaiting assignment to a new part of their island-kingdom. They have three choices as to where they can be assigned:

A Coastal Area with a small Archipelago that they will have to run missions to.
-Lots of ship-based combat
-Uses Stormwrack

A Tomb-City surrounded by a blasted waste-land
-Many Undead
-Uses Sandstorm

A Lighthouse Citidel on an iceberg
-Uses Frostburn and a wee bit of Stormwrack, as the iceberg is basically a huge boat.

Each of these areas will have a secret, optional boss monster that can be sought out and fought. But I only have a few ideas, and I'm looking for more supernatural type threats. So, i put it to you, playgrounders -- what sorts of monsters should i place in these areas?

What I'm Looking For

I'm looking for legendary opponents that will pose a fatal challenge to a party of 4 at 6th level, and be a significant obstacle of a party of 4 at 9th level.

Bonus points if you include cool equipment that comes from defeating the beast.

What I Have Now:

-Half Red Dragon/Bulette (CR 11ish)
This creature can be encountered in any part of the country -- its 00 on the encounter table for any environment.
The creature is extraordinarily deadly, with a more refined version of the standard half-dragon breath weapon (can be used one every 1d4 rounds). It also has DR 5/Adamantine.
The creature carries little treasure other than what is in its gullet -- currently a +2 Adamantine Longsword is caught in th belly of the beast, its exceptional construction the only thing keeping it safe from the creatures fulminating stomach.


Thanks in advance for your help

-Wayfare

[Cheesy74]

The big thing to do with boss monsters isn't to give the boss lots of abilities - it's to make the environment unique, interesting, or dangerous and have the boss play off that or be immune to it in some way.

Let's look at your current boss. Don't consider anything I'm about to say a cohesive guide - I'm just brainstorming to help you out.

I think it would fit best in the wastelands surrounding the tomb city (obviously this is up to you). It can breathe fire and burrow, so consider allowing it to do so beneath the ground, sending a geyser of flame and sand upward.
Its breath could turn the ground to semimolten glass, making it difficult terrain that deals fire damage.
You could even make the wasteland itself brim with hazards where it's encountered - it's a featureless plane, but near a tomb city, mass graves tend to show up. Unprotected in a hot environment, a lot of rotting bodies build up a lot of gas beneath the sand. Throw around some traps that explode when stepped upon or disturbed, dealing slashing damage from the sand and collapsing into a 10-foot deep pit (nothing deeper would really be reasonable) filled with the corpses. If you want to give the fight some other opponents besides the bullette (always a good idea), have the corpses animate. Or just have the pungent gases inside be an inhaled poison.

There's a huge number of possibilities for boss encounters, and almost none of them are related to the monster's abilities directly. Be creative with the environment for a memorable fight.

If you want ideas for the remaining fights:
Ship-based combat is already pretty unique, but if they'll be doing a lot of it, give them other stuff to deal with at the same time. Maybe the monster punctured the boat and they need to balance their efforts to kill it with patching up the boat or stopping it from sinking. Maybe other boats need their assistance while theirs is under attack. Consider using a giant squid (CR 9) attacking the boat alongside some weaker sea creatures like some Huge sharks.

As for the lighthouse citadel, ice is always a great opportunity for terrain-based combat, especially rounded, angled, or even moving surfaces. When your players are constantly forced to either fall down, stay put, or slide across the battlefield, their tactics will be forced to vary from your standard "Hit monster, hope it dies." As for monsters, look up force golems (MM5) and Ice Golems (Frostburn). Force golems are fairly easy to pile on (low CR) and really mess with a terrain fight well. An Ice Golem (CR 9) would be immune to the ice's slowing effect and be a tough combatant for the party to deal with while it's being scattered.

[BRC]

CR 11 is probably what you're shooting for here. What books do you have available?

That said, some ideas I had.
For the Tomb City
The Undying Crusader
10th level Necropolitan Fighter (He could also be a Warblade, a Crusader, or even a Paladin, altered so his Smite abilities work on anybody), he is accompanied by Five 5th level Necropolitan Fighters, all of which ride skeletal Warhorses.
A Lord whose name has since been lost to time. He once led a Crusade to purge the Tomb city of undead, and swore an oath that he would not rest until he had achieved his goal.
However, his Army had been poorly outfitted for the wastelands. They were caught unprepared in a sandstorm, and many of his men died. When the lord insisted that they push on despite these losses and their lack of preparedness, most of the army deserted. Furious, the Crusader declared that he would kill any men who deserted his cause in addition to purging the city of Undead. Most of his army fled while the Crusader, accompanied by his bodyguards, began to scour the desert, striking down any undead or deserters he meets.
The Crusader died shortly after, between battle wounds, the conditions of the desert, and his own madness it was inevitable. However, the fury that drove him continued to animate his body, along with those of his loyal bodyguards and there steeds. He continues to ride across the desert on his mad quest, attacking anybody he meets, assuming them to be deserters from his army, bandits, cultists in league with the undead, or simply anything else that comes to mind. He does not enter the city itself, but he remains firm in his belief that, had his men not deserted him, he could have taken it easily.
So long as The Crusader continues his quest, his bodyguards cannot die. If one is destroyed it will re-appear, emerging from the sands at the Crusader's side with the next sunrise.

If the PC's defeat the Crusader and his bodyguards, they can get his sword, a +2 Undead Bane Silver Greatsword, however, when used as such, the Sword is cursed, causing the wielder to fly into a rage at the sight of Undead or the prospect of retreat ( A Will Save must be made to not openly attack any undead the moment they are sighted, no matter how many, or how powerful, or even if there is a plan to attack them later. A Save must also be made to flee from combat while there are still enemies around, or to intentionally get out of melee range with an enemy the sword has struck). If the PC's manage to put the Crusader's spirit to rest somehow, perhaps by using the Sword to defeat some major undead in the City, this curse goes away.

Edit: I have him as a Necropolitan, because that's my go-to template for generic Undead, but you could have him as a Ghost, or a Death Knight, or anything else that fits the bill.

Edit: Also, about this Iceburg Lighthouse Citadel. How big is the Iceburg, is there a wilderness outside the Citadel, or is it just some ice. How big is this citadel, was it recently completed, or is it an ancient structure with only part of it secured and repurposed as a lighthouse, full of ancient hidden passageways and unexplored chambers.

[Land Outcast]

Well, I'll be back, but for now I'll just throw some "title" ideas:

A Coastal Area with a small Archipelago that they will have to run missions to.

Ghost ship!
The captain is a liche*, the sailors are skeletons, and some of them are ghasts. *perhaps a sea witch from stormwrack.

A Lighthouse Citidel on an iceberg

The Living Land
Make it an Elder Ice Elemental (use stats for Earth elemental), Awesome Blow makes for interesting fights in the cliffs.

Or maybe a giant... two frost giants for example.

[randomhero00]

1. Awesome, infamously known pirate. Actually has a blackpowder weapon (use whatever stats, but by the time the players get it, its empty) and a nice scimitar. He's very clever. He'll soften up targets with his ship's cannon if they can be hit from sea. If not he'll send in his crew first. He has a supernatural ability to drunk glug; after drinking a pint of this he gets +6 str, -2 cha, wis, and int. In this state he cannot be stopped (immune to sleep, stun, movement impairment, daze, etc.) until the beverage wears off enough (1d4 minutes).

2. Sandmummy. He has supernatural control over the sand, almost as if its awakened or something. He can use it to cover the party, blast them, soften them up, trap them, etc. He also has defile, which will drain all living things within 60 ft (2d10 no save) and give him 5 temp hps for each target he hits.

3. Hmm thinking either a Kraken that can break through the ice (making into a game of, you go that way and Ill pray and go that way) or an ice dragon.

[AslanCross]

The big thing to do with boss monsters isn't to give the boss lots of abilities - it's to make the environment unique, interesting, or dangerous and have the boss play off that or be immune to it in some way.

I totally agree. It's much more memorable to have the monster in a setting that's more memorable and advantageous to the monster. Even a very powerful boss in a flat, featureless environment won't strike the players as memorable. Even worse, it could be cramped in a small 15'x15' room, as is typical for most dungeon crawls.

[wayfare]

Thanks for the suggestions so far, guys! They are all great!

A bit more info on the terrain:

-Tomb City
This area is going to become central to the game at higher levels (15+). It is a magical citadel that was a remnant of a godwar -- a battle between deities that literally broke the world into a bunch of floating continents.

About 700 years ago, two smaller nations fought over this citadel: one revered the site as a holy relic, the other nation was led by a wizard who sought to use the machinery within to ascend to godhood. After capturing the city, the wizard cast a spell that, when magnified by the artifacts within the city, killed every living creature within 100 miles and destroyed arcane magic across the world (the only arcane classes are warmage, dread necromancer, beguiler).

The city was considered cursed ground for roughly 250 years, a blighted wasteland where undead roamed and the ashen statues of the dead (their literal corpses, reduced to volcanic ash) dotted the landscape. It was built into a Tomb-City shortly after the modern kingdom was established, after which the incidences of baleful undead dramatically decreased. The place is still powerfully haunted: incorporeal undead can form bodies from the ever-present ash that blows through the countryside, though many only manifest to uphold the king's law.

-The Coast
This is where the PCs are now. A large coastal town is ruled by a a Dwarven Baron (Expert/Cleric). It is the largest shipyard in the kingdom and the second largest port (right behind the capital). The PCs will largely be responsible for defending the nearby chain of islands, as the port is very well defended. The islands are under constant attack by a band of pirates who are warring with a group of Sahuagin -- whoever emerges victorious will attack the port.

The Sahaugin are trying to reclaim their surface temple from the pirates: an ancient Zaratan that the pirates are using as a massive raiding base. If the Sahaugin take the Zaratan, they will attempt to summon an aspect of Dagon when the game reaches the 15+ stage. If the pirates keep the base, they will lead a massive assault on the port city and destabilize the king's rule...eventually leading to a civil war.

-The Lighthouse
The lighthouse is a magitech construct that dates to just after the godwar, the last of many such devices that were constructed to make the seas safer. The lighthouse goes deep into the heart of the iceberg it sits upon, eventually leading to a portal to the elemental plane of water. The iceberg itself is crafted from frigid blue ice (1d4 cold damage/round), the only exceptions being white-ice paths that vein the quarter-mile iceberg and are tho only way to traverse the expanse without mystical protection.

The lighthouse is a powerfully magical place and currently houses a school of dabblers in the arcane. Most of the rooms in the lighthouse are locked, though the students are always trying to pierce the wards that bind those doors. Only the first 5 levels of the lighthouse are unbarred -- the remaining 13 levels have yet to be breached.

The lighthouse is currently used to guide ships through the misty north, though it can move up to 10 miles in a day if necessary. It has been used in the past to launch troops, as it can hold up to 3 ships of the line in its docking area.

No one is certain as to the true purpose of the lighthouse. A warmage currently in residence believes that it is a potent warmachine of some variety...

(and, in a way, it is. the lighthouse was created to control weather. The top of the tower contains a gateway to the elemental plane of air -- when both portals are active, a caster can manifest control weather in a massive radius, or can cast epic-level weather spells for the local environment)