LIGHT YAGAMI replies.

It's simple — you've misdiagnosed your own mistake, and the misdiagnosis is the only thing here worth correcting. The error was never the lie. People build serviceable identities out of small fictions every day. The error was announcing a claim you couldn't sustain, loudly, before you'd done the work to make it true. That's a tactical failure, and tactical failures are beneath anyone with your evident self-awareness.

So: no confession. Understand why. Confession isn't honesty — it's you asking your coworkers to absolve you, trading their comfortable goodwill for a moment's relief from your own discomfort. That's a poor trade. Let the marathon-runner die, quietly, the way I learned to let people believe an ordinary student sat across from them. You don't correct a misperception; you let it fade and replace it with results no one can dispute. Become quietly, undeniably competent at something real, and "she said she ran, once" becomes a footnote no one revisits.

One observation, though. You invented a runner because you needed strangers to believe your life was in order. That hunger — to be seen as together — is louder in this letter than any shin splint. Examine it. The lie was small. The need underneath it is the thing actually managing you.