By completing contracts you gain reputation and adventure rank. Adventure rank allows access to harder missions according to its Difficulty Level, while Reputation unlocks participation in different types of contracts, such as the outlaws, watchguards, or with a certain group of people. Some only need Adventure rank while others exclusively use Reputation, but it generally needs a part of both.
In some cases, it's possible to bargain your contract's reward. Even if there are no named rewards, you'll always gain experience. Abandoning or failing results in loss of reputation, while if you do missions that imply bad deeds you'll gain negative reputation, allowing you to build up Negative Reputation.
Negative Reputation allows you to access contracts of the opposing party, which are mainly focused on attacking or sabotaging them. Whatever, you'll also gradually lose access to their respective places. The Major Reputation follows the law of your current kingdom, having a negative reputation on that means you'll only be able to enter underworld locations.
A high-to-low scope of your reputation will be saved in your character's profile, so the game can remember if you had a negative or a positive reputation in the past, changing not only NPC's but also player's interactions, and that's why even if you have the required reputation, you won't be able to receive some missions. It's possible to slowly lower such extremes with time.
There are three categories of contracts:
NPC-based: which are received from NPCs to help NPCs.
Player-based: allows to attack or help player operations, generally being guild missions or commissioned quests.
Event-based: are given by the developers for players to advance within a season event. According to how the players do in these, the event can change courses and lead to a different big-picture narrative or difficulty level.
Contracts aren't separated by tags in-game, but they can be boiled down to a few different types of objectives, which is possible to preview by reading the quest's context or its requirements for completion. From lower to higher rewards:
{
Talking: speak to NPCs, for presentation or delivery of information.
Delivery: deliver items or objects, or move them around.
Gathering: collect a certain amount of items or objects.
Exploration: gain information or unveil something from a certain location.
Bounty: kill a certain amount of creatures, clean an area, or destroy something. A specific target to kill is also possible.
Protection: safeguard people and/or cargo until they are safe.
Expedition: "advance, conquer, and secure", focused on both exploring and conquering a location.
+Mission modifiers, which can be: Time, having a time limit to complete it; Moment, when such mission can be done; Action, which needs you to do it peacefully, stealthily, or aggressively; or Competition, where only the first ones to finish the mission receive the reward.
}