As I see it the one big problem Haruuc has is the instability that is plaguing Darguun. The problem comes three fold. First Haruuc is from the Ghaal'dar clans, not the traditional ruling clans of Dhakaani, thus not able to take the role of Emperor, having to settle for the rank of High Warlord instead. Second, even thought Ghaar'dar is larger and he has the support of most of the Marguuls clans, Dhakaani still holds large chunk of power that are key to maintaining his rule and power base. IF he losses what support among them he has then it could mean civil war and the down fall of the goblin nation before it even had the chance to start. The last is age, Haruuc is getting old and it is his personality and prowess that hold the clans together thus far, he needs an heir. So,seeing that Haruuc is a brilliant general he would logically come to the conclusion that if he truly want Darguun to survive the test of time it needs great leaders and a lasting symbol of the unity they once had. By Tradition he can not be that. The goblinoid people see the Dhakaarni clans as the rightful rulers, so Haruuc is going to need a foemperor or and Emperor that is more spiritual in nature then governmental. This were the idea of modeling the governmental and societal aspects of the goblinoids on the Japanese of the early Edo period comes in to play.
The Japanese in their early history were a group of waring clans that had a continual civil war with brief periods of stable rule by the emperor of on faction or another. But one continual fact is that they saw the ruling family (clan) as begin of divine origin. In their mythology the Japanese that land Japan was created by the Sun Goddess, then the role family and finally the rest of the Japanese people. This meant that that even though they were not always in power the Imperial Family always had the respect of the people. I see the gobinoids of Eberron being culturally similar to the Japanese of old. Both people place a high value on family and personal honer. Clan and class structure of the two societies, as well the martial prowess of their warriors. I love the picture of Haruuc in the ECS, it has a lot of Samurai qualities to it.
Now that I have given the background of the idea, let me get to the heart of the matter. I need ideas for running a continual storyline of how 4 goblinoid heroes were called from the clans by Haruuc to quest for the lost bloodline of the Dhakaani Emperors. They are to fin out if any members of the is line are still living and which one is worth of the title Emperor. Although the final choose id with Haruuc one goblin can tell if another has honer or not. They are to find only worth bloodline heirs all others most be cut out of the running. Even though Haruuc only intends to use the Emperor from the Dhakaaani clans as a political and symbol with no real power it should go a long way toward building lasting bridges between the clans and securing the rest of the loyalty of the Dhakaani clans so that Darguun will continue on after Haruuc's death. Haruuc also needs a heir so he also will be asking for the help of the heroes in this department. The Great Lhesh Haruuc Shaara'Kor cannot just mate with any one and all his time and effort is need to to run and maintain Darguun. I wan the PC to have to fin an NPC that is worthy of being a Shoguns wife.
I want to have the PC travel Khorvaira far and wide searching old ruins talking to lore master to fin clues to the mystery bloodline campaign. This is bit of a different type of campaign then my group has run in a few years. I am sorry to say that we have fallen on hard times with the lose of a few of the better roleplaying members, we have fallen in to a monster of the type of mentality. The Campaigns we tend to run have little of a continual plot that really grabs the players like it did when we first started out. I have been working to breath life back into the dead skills of roleplay and I belief the a go mystery campaign will really help out. So I want to make it real special with lots of NPC to interact with and a good mystery that will leave them wondering where they will end up next.
Edit: This is for the 3.5 system so if you are going to comment on ideas for encounters or spells please put it in those terms. But other wise and plot ideas can come any way you can write them, well except in piglatin. I was never any good at that.
Bugbear Druid from the Marguul clans of the Sea Wall mountains
-a follower of the old Druidic sect the GateKeepers. His clan can trace their ties back to the fall of the old Dhakaani Empire and the Darekyr Wars.
-his sect of Gatekeepers is mostly made up his clan shamans so they have taken on so goblinoid cultural aspects to the religion. like the value of strength and purity.
-hate mage breed animals and animals that are specially breed like the Valanar horse, sees them as unnatural.
Blue Goblin Beguiler/enchanter(psionics) from the Kesh Volaar
-although male in a normally female role he has found a place at the Dhakaani courts as a lore master
-sees master of the arcane arts as tool to over come his lack of martial prowess, why fight when you can force your enemies to fight each other.
-sometime a word can cut through a mystery that a sword can not.
Hobgoblin Rogue/Assassin from the Shaarat'khesh clan
-this silent blade prefers the reach of a range weapon over that of his knife. Sometime studding your enemy from a short-bow shot way is easier then have to sneak around in the shadows.
-honer does not only come from the clashing of blades of the samurai warrior, it also comes for the sacrifice of those in the shadows that keep the dishonorable from costing the lives of the Honorable
Hobgoblin Samurai from the Kech Volaar clan
-we rewrote the class using the CW and the OA versions, because the CW has a few class abilities that were worth being called an ability,but most of the abilities were just feats under a new name so to give the player more freedom I just went with fighter bonus feats.
-melee and honer that is the core to any kingdom, not only is he the melee center, but the the moral center of the group as well
Dhakaani
Kech Draguus
Kech Nasaar
Kech Shaarat-"Bladebearers"-leader:Ruus Dhakaan
Kech Uul
Kech Volaar-"Wordbearers"-leader: Kurac Thaar and Tuura Dhakaan
Shaarat'khesh-"Silent Blades"
Taarka'khesh-"Silent Wolves"
Ghaal'dar
Gantii Vus-"Hungry Flame"-leader Munta the Grey
Ja'aram-"Bright Anger"
MurTalaan-"Horned Shoulder"
Rhukaan Taash-"Razor Crown"-Lhesh Haruuc Shaara'Kor
Marhaan
Ghaal Sehn
Pir Galaac
Gan'dauur-"Eaters of Sorrow"-rebel clan of the Ghaal'dar and an off shoot of Gantii Vus
Marguul
Kallkor-leader Mograath-bugbears that refuse to bow to the hobgoblin lead government of Haruuc
unnamed clan-leader: Makka
[SPOILER*]
I. An Tavern/Inn at a small Dhakaani Clanhold south of Volaar Draal
A. The heroes answer a summons of Haruuc. Meeting their guides at a point outside the terroritory of the Ghaal'dar clan.
1)Tar'gorn of the Bloodyblades, a personal guard of Haruuc, bearer of the standard of passage. a Ranger and Samurai
Bree Dhakaan, a dirge singer and mate Tar'gorn
2) The Tavern has several tables of groups of travelers, large group of bandits, 3 Gnoll Adventures with a Dhakaani relic from Droaan they are bring to market, 4 local hobgoblin guard, and 5 human adventures. Tar'gorn and Bree sit alone by the wall watching before talking to players.
3) In walks new large group of Bugbears fresh from the road, rain soaked they want the table where the players sit because of the closeness of the fire. This is a test, to see how they react toward other goblinoids. Do the Heroes have Honor and wisdom or are they simple brutes of crude clans. Was Haruuc rough in choosing these heroes for the task. The Bugbears are lead by a Bugbear name Heath the Heavyhanded, a warrior monk and memeber of Tar'gorn team. The Bugbears are just local from down the road.
B. Start with show of force and a test of strength. Heath will spit on the floor before the party and pound his chest. Then come the demained for the table. If will challenge the smallest character to physical test of strength acting if had no Honor)
1) If the Players dont try and kill Heath the meet Ta'gorn
2)after spending the night in the inn the move out to Rhulaan Draal
II. The Road To Rhukaan Draal
A. Targorn adn Bree lead the way along a road with the banner of passage.
1)The bandits from before shadow the group. They attack ofter two days
2)Random encounters
3)role paly to try and set tone of the campaign, talk about history of Darguun, Dhakaani and the wars with the elves, humans and Daelkyr.
B. Rhukaan Draal
1) Here Haruuc tells them what he wants of them
2) Tells them to run down any lead they can to find a new canidate for the Role of Emperor, because the leading contenders will only use the position to undermind him and serve their own clans interest over that of Darguun. Making it very clear to PC that he will remain in charge and that he intends to find a worth mate to produce a heir.
3) The Emperor must be a goblinoid of both honor and spiritual wisdom. Someone learned in the oldways of Dhakaani and able to enbrace the future of Darguun. The bloodline is the most inportain symbol this canidate will have for the right to hold the position.
4) Haruuc will send them first after a Gnome who before the fall of Galifar studied much of the goblin history of the Dhakaani Empire. He is thought to know more that any one person alive, being over 300 years old.
C. Surfieo Sky'fan Rumtongue
1)Surfieo is an old gnome now retired thought to live in western Zilargo.
2) Know to be an explore, adventure dungiuneer and tomb robber (goblinoid outlook) in his younger years. He was also know for his knowledge of the divine lore of Galifar. Was a teacher in sharn for a while but most of his time spent working for the Kerronburgh liberay.
3)Surfieo is to be taken alive and he is wanted criminal in the eyes of the Kech Volaar clan so he is worth a reward to them.
III. Over the SeaWall Mountains to Zilargo
A. Party cross over to Zilargo by the passes known only to some goblins in SeaWall Mountains.
1) The party needs to quickly and quietly while looking for Surfieo. The gather information check is DC 25.
2) They find him not in Zilargo but in Breland just over the border in a small village where he live with his grandson.
3)Surfieo's house is on the outskirts of the village. Small size house but medium size characters can enter, just fight at -2
4) Surfieo is old but not dead, he is a summoner of high level. The house sits atop a large to huge earth elemental.
B. After the Battle with Surfieo the party must get his research, because he is not very forth coming. But gnomes are know for their love of information and tend to write and keep all they can.
1) The party has a choise here Sharn or Kerronburgh, both ay have the research they need. The correct answer is Kerronburgh to the great liberay. This level of knowledge is keeped close to home not let out in to the world like at a place Mongrave.
2) If the party travels to Sharn set up side quest and have Dragonmarked house start pocking in to see what this party of goblioids is looking for.
IV. Theif at the Korranburgh Libiray
A. The liberay is guarded by the Trust and Kundarak DWarfs.
1) Gnome Rogues and Wizards
2) the Dwarves are fighters and rogue
3) A troop of Warforged also work within the liberay as a last line of man defense.
4) Traps and trickery in the liberay, make a maze and a number of traps for the party to run through.
B. After the party find the research they have to get out of Zilargo
1) They travel back to Rhakaan Draal with Surfieo.
2) Haruuc rewards them with riches if they got in and out quietly or punishes them for almost failing and revealing the plot to gnomes of all things.
3) After the reseach is looked over and Surfieo is properly questioned they are sent to Khraal to look for more clues and to enter a hidden chamber the Surfieo found on his last trip there just before the out break of the last war.
C. The party is told off a hidden chamber that no one has explored or seen for over a 100 years. Events of the last war and the fall of Galifar stopped any more exploration of the area.
1) In the chamber maybe a complete list of the line of Emperors and which Dhakaaani clans they belong.
2) Also in the Chamber maybe items that have have historic value to be traded to the Kesh Volaar clan for their loyalty.
V. The Ruins of Khraal
VI. To Droaam to visit the Seer of Suthar Draal
VII. To the Eldeen Reaches and the Warden of the Wood
VIII. In the Shadow Marshes and Taarn Draal
IX. Back to Rkukaan to Report in Person
X. The Search for Lost Fortress of Taer Sadaen
XI. The Prince fo Dhakaani
XII. The Road out of Valanar
XIII. The Crowning and the Dragonmarked Plot
XIV. Civil Unrest and the War
XV. Valanar Burning
XVI. The Meeting at ThornHold
XVII. The Rebirth of Galifar
XVIII. The Lord of Blades, and the Cannith Plot
XIX. Down Fall of the Good
XX. The Undeath of Galifar and Dhakaari of the South
[/SPOILER*]
Your party composition features one of my favorite combinations, storywise: the goblin/hobgoblin/bugbear druid. To me, "goblinoid who can turn into a wolf" is spelled "BARGHEST." 
In Martial Power 2 there's an epic destiny called Legendary Sovereign for fighters, paladins, rangers, and warlords. In a nutshell, it's the "it's good to be king" destiny, and provides the character with some fun perks while in their home turf. For a campaign about choosing an emperor, it might be something you could adapt for one of the PCs.
EDIT: Sorry, post lag. I didn't see the outline. Looks like you are headed in another direction. Maybe there are still some useful ideas. I'll have to check out the outline.
First I would start by figuring out which factions would aid or hinder this quest. Here's some ideas for NPCS:
1. Obviously the Dhakaani would try to stop the PCs from finding a suitable queen, but might also be interested in finding the lost line for themselves. So you could have someone try to infiltrate the group and turn on them when the time is right. Sounds like a sneaky goblin to me, often overlooked.
- Maybe Haruuc sends a guide to help the PCs, but this character replaces him before they get a chance to meet.
- Or maybe he trails them for a bit and tries to replace an NPC they're about to meet to throw them off the trail
2. For tracking geneology (albeit goblinoid) the Blood of Vol might be helpful. A goblinoid Blood of Vol priest? There could be a small group of followers that have been trying to track down this line also. Would they be helpful? It might be interesting for a change. The PCs would probably be suspect the whole time and really the BoV priest just wants to genuinely help.
- Maybe he's totally uninterested in politics, just wants to find out for scholarly reasons.
- A trip to the Crimson Monastery in Atur would be interesting. They need this NPCs help to gain access (or at least know where to break in.)
3. Maybe there are Dhakaani ruins in Valenar. More than that, there is a survivor living here. Maybe a slave of the Valenar, captured during the Last War. The NPC might know she's a heir, but not the full extent; the ruins will tell the tale. Or the ruins are really in Q'Barra or the Endworld Mountains and she has an ancestral "key" that opens them.
Your party composition features one of my favorite combinations, storywise: the goblin/hobgoblin/bugbear druid. To me, "goblinoid who can turn into a wolf" is spelled "BARGHEST."
In Martial Power 2 there's an epic destiny called Legendary Sovereign for fighters, paladins, rangers, and warlords. In a nutshell, it's the "it's good to be king" destiny, and provides the character with some fun perks while in their home turf. For a campaign about choosing an emperor, it might be something you could adapt for one of the PCs.
Thanks for the input, but I guess I forgot to mention that this was a 3.5 game using soem house rules and the a few things from the Pathfinder rule. I tried to get in to 4.0, over half the group even bought the core books when they first cam out. I think it was the fact that we can build a 3.5 character that is both balances and optimized of the top of our heads, that really stopped use from moving over to 4.0.
I like some of the things they didwith the ew system, but there is also a lot I did not really like. I Was also not a fan of the fact that all th fluff information on the realms and Eberron was not going to be put in to book for and you had to pay play if you wanted to use the newer article. If I am going to down money I want soemthing in my hand.
But Thanks anyways!!
I stilll would love to hear any ideas on the plot or to have you point out any large plot wholes. I need all the help I can get on this and it would be nice to have another DM outlook on the game. "Fresh eye always help even when they are trying not to", just alittle saying I picked up from somewhere
Hm-- if I'd been reading a little closer, I might have been able that you're using 3.5 based on the mentions of the beguiler and samurai class. My bad! (Though, a 3.5 edition would-be barghest could still be a druid, using the alternate shapechanging rules from Players Handbook 2. I love that version of the druid-- vast improvement, in my opinion.)
I know the overarching quest is finding a queen for the Lhesh so he can produce an heir... but have you considered the possibility that over the course of all these quests, one of the PCs may prove themselves a worthy ruler? They'll be out there proving themselves, establishing honor and reputation, overcoming obstacles... The Lhesh's goal is to find a worthy successor, and here are four people demonstrating power and finesse left and right! Again, just a thought.
You've got a very good take on internal politics, but have you also considered outside parties that might want Darguun to fail? Darguun liberated its territory from Cyre; if the nation collapsed, the displaced Cyrans might have a shot at a new homeland. Then there's the Valenar, who are always looking for a fight. If they interfered enough in Haruuc's line of succession, the elves might provoke the invasion they always wanted. Just a suggestion for when you need new adversaries to toss at the party.