Complex sentence: Thus their fates are completely sundered from that of the Elves, who do not die until the world dies; if slain by violence or ill chance, or by wearying at the last of the passage of centuries, they are gathered in the Halls of Mandos.
Split into simpler sentences: Thus their fates are completely sundered from that of the Elves, who do not die until the world dies. If slain by violence or ill chance, or by wearying at the last of the passage of centuries, they are gathered in the Halls of Mandos.