Chain quests are multi-part quests which must be done in a specific order. These different parts form a chain of single quests that have to be completed one after another to reach the final mission goal. Chain quests may take place in a single chapter, or (such as the Blue Chain quests) may span two or more chapters.
Chain quests may contain any number of single quests; thus you can have a two-part chain quest like Pesky Pirates, or the large fifteen-part chain quest The Undead Legion.
Because chain quests are, essentially, a series of single quests, all or part of a chain may depend on a character's alignment to either the light or shadow campaigns.
Common Chain Quests
This is a list of chain quests in Sacred 2 Fallen Angel that are exactly the same no matter what alignment or class a character has.
Path Specific Chain Quests
This is a list of chain quests where character alignment affects either the whole or part of the single quests in the chain. They are listed below depending on whether they are 'All Light' (character must be light aligned to do any of the chain), 'Mixed' (some of the single quests in the chain are different depending on whether your character is light or shadow aligned), or 'All Shadow' (character must be shadow aligned to do any of the chain).
Blue Chain Quest Lines
A blue chain quest line is a group of quests specific to each character class which take place across the entire campaign, whether light or shadow. Blue chain quest lines, like any class-specific quest, are denoted on the tab and world maps by blue markers on the map. On screen the ? and ! marks are in a colour specific to the character class, Light Blue for Seraphim, Yellow for Shadow Warrior and Dragon Mage, Light Green for Dryad, Dark Green for Temple Guardian, Dark Blue for High Elf and Red for Inquisitor.
(Note that when in Multiplayer, you'll see additional marks for quests that are not for your class. However, despite being able to see them, you can't complete those not for your class)