Trovis Disappearance

The Trovis Disappearance is a mysterious historical event which took place in RY77 in the city of Sijan. Since a few years earlier in RY75 the Scarlet Empire had stationed a small garrison in the city on the Isle of Trovis, a talon drawn from the 4th Imperial Legion. Official Imperial Legions records state that the garrison was withdrawn in RY77, but a discerning eye will note that the records do not state to where they withdrew, and the names of officers and soldiers from the talon never appear in records thereafter.

The later defection of the 4th Legion's strategoi Vondy Beulen has caused some to whisper the talon at Trovis was an early defection, while the powerful presence of the dead within Sijan births theories the garrison might have been slain by some undead monstrosity, but to this day no certain answer has been found.

Source: this is Exalted canon and now also a Star Rail reference.