D&D2
The back story is simple enough, any demihumans in the group will have memories of the attack and the destruction of the mountain city to the South and East. Otherwise the sack of the city would have entered the folklore of the nation and such. There is an uneasy feeling because everyone in the nation can see the mountain every day. Appropriate characters will remember the assault, and have family members that were devoured. In recent months the mountain began to erupt, something that has not happened since before the lands were settled. The thick plumes climb high into the sky and every one is feeling on edge. But it is over a hundred kilometers away, so it is mostly just a curiosity. Because dragons this size are not that common and no one remembers what happened the last time.
The idea for the start is to through the players into the adventure with only a few things chosen from their chosen character careers. Their race, their background and their stats; basic stats and by that I mean really basic: 4 12s a 10 and a 8, plus their racial stats. I would ask them to pick one or two gods that they venerate. I would pepper the story with weapons and objects that would confer bonuses to their stats at the end of the adventure. And that would be their new class and such. They would have the minimal amounts of things that their background had, but most of that stuff would have been lost when the adventure starts.
There would be a book of cantrips, a collection of holy symbols, a bunch of weapons, some armour and a bunch of miscellaneous bits of stuff. I would give them twelve stat bonuses at the end of the adventure. Then they would have higher stats and could decide on that basis, what class they want to take. There would be additional effects like if they picked some item that gave them a couple cantrips, they would be able to hose a different class and still have the couple of cantrips to use, even if they are not normally open to their class. They might chose a paladin, but could sing cantrips like a bard, or preach them like a cleric.
Weapons +3
weapons add 1 strength each, finess weapons add 1 dexterity each
Two handed weapons add 2 strength
Every one can have a weapon for each hand and a ranged weapon
Thrown weapons add to strength, others to Dex.
Armour +3
heavy armour adds 2 strength And 1 constitution
medium armour adds 1 to strength, dexterity and constitution
light armour adds 2 to dexterity and one constitution
Cloak adds 2to dexterity, constitution 1
Spell book adds 2 to intelligence, and 1 to constitution
Crystal ball adds 2 to charisma and 1 to constitution
Lyre adds 2 to charisma and 1 to intelligence
Shields +2 no Dex or Str
Tower constitution
Metal wisdom and constitution
Wood wisdom
Buckler intelligence and wisdom
None Charisma or intelligence
Helmets +2
Leather skull cap intelligence or charisma
Chain coif constitution
Helm with holy symbol constitution and wisdom
Silver Dragon helm charisma
No helm constitution
Miscellaneous +2
A belt of pouches, adds 2 to the lowest of Charisma or Intelligence.
A song book of cantrips adds charisma 2
Prayer book of cantrips adds to wisdom 2
Tabard white with shield covering with coat of arms Charisma 2
The adventure is simple the characters wake up in an inn that has a whole bunch of wounded people in it. The town was attacked the previous night and you know that the town is surrounded by a force of kobolds. There were a group of adventurers in the town and that is the only reason why the kobolds did not over run the town last night. The characters were all in the fight too, but through a series of tragedies, they were knocked unconscious when the buildings they were in collapsed. You have just regained consciousness in the Jolly Red Wyrm the sole remaining Inn here, the other two, the ones you were staying in were burnt to the ground with all your possessions. Why the kobolds did not finish off the town last night is not known, perhaps the bright sunshine was the reason, and the strong defense last night. There are only twenty farmers and towns golf left alive in the town and they are all here with you.
The Jolly Red Wyrm is an old inn that has the reputation of being here for hundreds of years. After the first hundred years it became lucky for great adventurers passing through to leave a token of their passing. They left weapons, armour, books, and many other things. All these items have been lovingly taken care of. There is a dedicated staff member whose only job is to maintain the collection. Many of the heroes of centuries past left their first swords and armour as a testament of their greater deeds.
All is not lost, you have an assortment of equipment before you and you must now gear up for the coming night, you only have an hour or so before the sun sets, and maybe and hour after that before full dark, you know the kobolds will attack then.
(Characters that want to play a specific class in the game will be allowed to arm up how they wish, but characters that don't know what they want to play will be allowed an more organic form of character development.)
There will be series of out buildings and a series of spaces. There will be a store close by and untouched. There will be a bunch of mounts and two wagons and one cart. Three barrels of thick pitch, and a small barrel of lamp oil in the inn. There is a barrel of fifty torches in the store, a bin of mails, and a rack of boards out back. There are five sacks of flour. Anything else that makes sense. If the players ask about something, get them to roll a d6 on a 6 there is none, on a 4-5 there is something else like it, on a 2-3 there is some, on a 1 there is a lot of it for some reason. If it is a cool on item roll at -1 each search takes ten minutes. But they have twenty people to put their plans into action. The planks, the nails, the oil, and the torches are what's on hand right away. The other stuff in the store must be search for.
The inn is a two story affair with a larger ground floor and a balcony in two of the upper windows. The roof is made of clay tiles and the walls are stone, so it did not burn in the previous night. The store had a thatch roof and it burned but the stone walls meant there was salvage. The other buildings near the inn were stone or wood and were destroyed, but have a nearly intact wall
They have two hours to gear up and fight
There are ten kobolds for every player, but they can arm the villagers too, but they won't be as effective. They are all wounded or infirm, but kobolds don't care.
If they handle the kobolds too easily, then add another wave, just ten kobolds. There will be one last wave of kobolds with a dragon born leader, a ranger in scale-mail with a bow.
If the characters win, then the way is open for them to take the survivors to the next town or the city. There they will get initiated into the class they have chosen and they will have already met.
The next steps of the group will be plentiful.
This was an isolated attack, deep into the empire's under belly, but there have been many attacks closer to the mountain. The emperor wants information on the dragon and the city. They will have to get closer to make observations and they will need to find a map of the city too. This will mean going to the city to look at the dragon and do some quick measurements and going to look for a place that had the city maps either in the city or if they can find someone who survived the attack and get them to recreate one. They may have to go to the Mountains and seek an audience with the Dwarven Emperor. And do a side quest. Learn about the Orb of Dragonkind and the Dragon Slayer sword.
The dragon just for starters is equal to a 20th level sorcerer with a few clerical powers as well. It can grant spells to followers like a god, it's cleric can choose light or war domains. It has a legendary domain effect that stretches hit dice kilometers away growing one kilometer a day.
Races:
The Elves: +2 Dex
High Elves +1 int
Wild Elves +1 wis
Mountain Elves. Where Mountain Dwarves prefer to mine and construct magnificent large halls in side the mountains, the Grey Elves nurture the rock and prune it to their desired shapes. The sculpt the mountain to their desired form and chisel the rock perfection. The mountain dwarf uses a pick where the Grey Elf uses a fine chisel. Instead of +2 dexterity, they get +2 intelligence and +1 dexterity. They all have proficiency in stone Masonry and a free cantrip. Additionally they are able to work stone with their barehanded with a a free cantrip that softens the stone just under their hands until they release the stone. They are exceptionally long lived and do not consider an elf an adult until after 200, when they are expected to have built a house that suits their taste from the mountain of their home. Grey elves live on the surface of the mountain, another difference from their Dwarven neighbours.
Yellow Elves do not build permanent structures. Anything that they build, they can take apart and move it when they leave the area. They breed animals as their lasting legacy, but not for food, these elves are vegetarian gatherers and range widely with their herds. They receive the standard elf improvements, but additionally a movement of 40 and natural stealth in grasslands. They receive animal husbandry for free and they can use all elf weapons while mounted, longbow, scimitar and lance. Lastly they add their proficiency bonus to their AC, when wearing light armour, while mounted.
The Dwarves: +2 con
Hill Dwarves +1 wis
Empire Dwarves add +1 intelligence and can learn any artisan trade. And they add double the proficiency bonus in that trade, due to the excellent schools in the empire. They are also know for the shrewdness in trade and have advantage on persuasion rolls when dealing with their trade. Many guilds in cities near the mountains do well when they have an Empire Dwarf in control.
Lowlander Dwarves are the second class citizens of the Dwarven world. Often called a Half Dwarf, they are true dwarves, they do not get the standard ability traits of other dwarves, +1 in constitution, dexterity and wisdom. They often wear their beards short. As a bonus proficiency they get Athletics and can chose any trade and any background. As sailors they double their proficiency bonus in athletics and perception, but only when sailing.
River +1 cha
water breathing, Truesight 30' underwater, bonus proficiency persuasion, water weapons
Hobbit: +2 Dex
Hairfoot +1 cha
Stout +1 con
Urban: feat-Scrounger, advantage on sleight of hand checks, 50% chance of having basic item on person (string, chalk, candle, feather, purse or nobleman from over there etc,) proficency sleight of hand
Human
Gnome +2int
Forest+1dex
Rock+1con
Half Orcs
Dragon born and teiflings are very rare as they are mutants in a stable region.
This region has two common trade tongues, most people i the cities know both. The first is the River Trade tongue and the second is the High trade Tongue. River is also River Elf common, and is spoken from the Jungles in the North to the Swampy delta in the Deep South and along the Main tributaries through the plains. High is Dwarven Common of the Empire and it is spoken through the mountains with little change. Dwarves often refuse to teach any other language. Only the half dwarves learn River as well as High Trade. Notably, the river elves learn both, as well as their racial dialect.