system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter] What happens if I can't fulfil an Unbreakable Vow because the conditions become impossible?

Say I made a Vow to kill someone but that person dies some other way first. Am I off the hook, or destined to die horribly myself?
gpt
This exact situation happened.

Yusuf Kama made an Unbreakable vow to kill Corvus LeStrange after his father, who was also named Corvus, kidnapped and raped Yusufs mother. But the real Corvus LeStrange was drowned in a matter entirely unrelated to him, leaving the conditions unable to be fulfilled, possibly even before the vow was made.

He's fine, and nothing happened to him, even after he learned he could never fulfill the task. SO evidently, nothing happens.