Dark Descent Weekly
Dark Descent is a dungeon separate from regular dungeons (meaning that it does not count towards the daily or weekly dungeon limits),
but rather has a limit of 3 attempts per week per character. There is also a weekly quest that can be obtained at the Stonehill Dig Site in Perion that gives several hundreds of Havi Fruit as a reward. However, this quest doesn't seem to be available yet, or has been removed.
See the guide to clearing Dark Descent here