Joining the Blades in The Elder Scrolls IV: Oblivion has no downsides and is generally recommended. When you join, you gain free access to the Blades' hideout called the Cloud Ruler Temple, which houses an armory with free weapons, ammo, and armor, including the Blades armor set. You also receive the Akaviri Katana as a reward, a place to sleep, and can loot many valuable items there. The Blades do not have a separate faction questline, and joining them does not affect your standings with other factions or the main storyline, which can be completed regardless of your choice to join. The invitation to join occurs during the main questline after completing the Weynon Priory quest and reaching the Cloud Ruler Temple. There are no special responsibilities or negative consequences tied to joining the Blades, making it a beneficial and low-risk choice in the game.
