Achievements are unlocked by participating in a variety of activities throughout the server. The achievements system has also been customized to track the progress of your entire account instead of each individual character, so once you unlock an achievement, it's unlocked for your whole account!
Each achievement you unlock will give you an amount of points depending on the difficulty of the achievement, which are also used as experience for your achievements level! You can see your current rank and experience in the top left corner of the achievements window, which will also show you how many points you need to progress to the next level.
You can check how many points an achievement will give you by looking at the number to the right of its name in the achievements list.
Passive Stat Boost
As you complete various achievements, you will receive a permanent passive stat bonus on your characters based on your achievements level. This bonus will provide +1% max HP and +1 to all of your stats for each achievement level, and will apply to all characters on your account, including new ones!
Note that this passive boost will not be applied to level 1 characters, to avoid an unfair advantage in Novice events.
Some achievements provide small item rewards when you complete them. These can be retrieved by simply clicking the "Collect" button in the achievements window, and will be mailed to your current character.
Some achievements will also provide titles that you can use on your characters. These will be displayed before your character name. Your title can be changed by opening the equip window (Alt+Q by default) and going to the Titles tab.
There are also a number of temporary achievements which will be unlocked temporarily when you meet specific conditions. These can be found under the Feats category, and are typically related to rankings or similar accomplishments. The achievements for total completion will be unlocked until new achievements are added and your total progress drops below the required percentage.
Ranking achievements are based on the previous ranking period, and will be unlocked for the duration of the current ranking period.