It could be eve's rework, but it seems quite noteworthy to me how similar both situations are.
**Tryn's bio **
He staggered to his feet - barely able to take hold of his sword - steeling himself for the decisive confrontation with the shadowy being. But the dark figure did not even lift his blade, and instead gave Tryndamere a knowing smile as he withdrew into the shadows.
"With sword in hand and rage in his heart, he is now on an undying quest for vengeance against the one who destroyed the life he once knew."
Vayne's Bio
"An unspeakably beautiful, horned woman stood before the bloodied corpses of her parents.
Vayne screamed in agony and terror. Before disappearing, the demon looked down at the young girl and flashed her a terrible, lustful smile.
Vayne tried to brush the bloody hair out of her mother’s eyes, but that haunting smile lingered in her mind, growing and consuming her."
"It was a smile that would fill Shauna’s veins with hatred for the rest of her days."
She doesn't have any weapon that we know about, but what about the darkin dagger? a small and easy to miss weapon that vayne wouldn't have seen in the shock of the moment.