After completing enough floors, you will unlock the ability to acend. Ascension sends your Knight back to the first floor of the dungeon and all of your equipment will be replaced with the Rusty Sword, Worn Armor, and Old Cloak. However you will keep your level and experience, as well as all the skills and runes you have earned. You will also get special tokens that allow you to purchase permanent bonuses for your knight. Make sure to sell all your equipment before you ascend.