Ueda Dou, an unlucky guy who died for unknown reasons.
As for why he didn't know the cause of his death?
Quite simply, he lost his memory.
The system in his brain that is comparable to that of artificial intelligence tells him that as long as he completes the task and accumulates enough energy, it can happily leave its host and wander around in various worlds.
So why is it said to be comparable to artificial intelligence?
Because the system has also lost its memory.
Intention: Write something happy