There's basically no story to speak of. You rescue your siblings after you reach clan tier 1, then there's the Neretzes' folly, which tells the story of the battle of Pendraic castle from the perspective of (I think) 16 or 17 people, of which you "only" need to talk to 10 of. Then you talk to Istiana and Arzagos, hear about their perspectives on the empire, collect the 2 other parts of the dragon banner and choose to give the banner to a faction (empire or barbarian, you can also choose to create your own faction which can also be imperial or barbarian depending on the culture you choose for the kingdom). After you give the banner, there's no story except some campaign only unique cutscenes (by cutscenes I mean the animations that play when you get married, have a child, become a vassal, etc.) and 2 different endings depending on whether you chose to support the empire or barbarians that look like the intro (just look at them on youtube).
After giving the banner, the campaign devolves into a ****fest of you trying to get as much territory as possible while a conspiracy caravan or party spawning anywhere on the map and you having to stop them. When you fail to stop them, because you will fail, you're pretty much set up to fail unless you want to go insane (or unless the faction you're part of already pretty much controlled the world before giving the banner to a faction) all factions declare war on you and the late game becomes an even worse grindfest.
The campaign just falls flat, you can't even face off against Istiana or Arzagos, I don't think you can recruit Galter (or whatever the name of the bandit at the start was) or Istiana/Arzagos (the one you signed up with) as a companion. The game doesn't give you a badass conspiracy army consisting of a large number of elite units consisting of different cultures to defeat as a one time endgame boss. It could've given you a quest to conquer the settlement where Istiana/Arzagos (the enemy) resided in before you gave the banner and then pulled a switcheroo on you by making you defend the settlement against the conspiracy giga-army led by your arch enemy, but no. The campaign after a point just stops giving a **** and tells you to straight up conquer 1/3 of the map. The conspiracy quest could've been a timed quest that increased or decreased the strength of the conspiracy army based on your actions regarding the conspiracy caravans and whatnot (a score of 1000 being +1k men, a complete quest failure would be a score of 2000, meaning that the giga army would have +2k men, a successful quest would decrease the number of men to the base number of 500 to 1000, etc.).
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