Myth: Susanoo Is Simply a Technique Fired From the Eyes
SPOILER!
The eyes are required to awaken it; the manifested avatar is a different kind of ability.
Susanoo is associated with awakening Mangekyō in both eyes, but once that ability has been acquired it does not behave like Amaterasu, Tsukuyomi or Kamui, which depend on the particular eye carrying the technique. Madara can manifest Susanoo after resurrection while he has no eyes in his sockets, demonstrating that losing access to the physical eyes does not automatically erase an already-awakened Susanoo.
Why it matters
This is why "Madara had no eyes" is not evidence that the story forgot its own rule. The important distinction is between the condition for awakening Susanoo and the condition for using an eye-specific Mangekyō technique afterward.
Myth: You Have to Kill Your Best Friend to Awaken Mangekyō
SPOILER!
Traumatic Loss Is the Pattern; deliberate murder is not a universal ritual.
The Uchiha history around Mangekyō turns grief into a dangerous instruction manual. Characters come to believe that killing someone close is the route to power, but the actual awakenings shown in the story are tied to overwhelming emotional trauma and loss, not a standardized requirement that the future user personally murder a best friend.
Why it matters
That misconception is part of the clan's tragedy. A power awakened through grief becomes something later generations can misread as requiring violence, helping the pursuit of the eye create exactly the kind of loss that awakens it.
Kakashi Is the Exception That Explains the Rule
SPOILER!
Transplanted Mangekyō · No Uchiha Body · Kamui Costs More to Sustain
Kakashi can use Obito's Mangekyō because the transplanted eye retains its ocular ability, but his body is not naturally built around the Sharingan. The result is a version of Mangekyō use defined by unusually severe chakra cost and limited endurance. During the war, the brief return of both of Obito's Mangekyō and his chakra allows Kakashi to demonstrate what the complete pair can do at a level he could never sustain with the single transplanted eye alone.
Why it matters
Kakashi separates possession of a Mangekyō technique from being an Uchiha. The eye carries the ability, but the body using it still determines how practical that power is.
