[HMM I OFF TOURNAMENT] "Company"

He could have escaped during a battle with a neutral faction, or bribed his way out during a battle with another AI.
Added 2 minutes later
and... generally, I think that when a hero "dies," he loses artifacts.
Am I right?

Based on daily saves, you can determine with 99% certainty whether there were clashes between AI factions!
In Heroes 1, an artifact is only lost if the hero falls in battle against another hero.
Want to collect more artifacts in one place? :D