(もと) You can use this about an ex-lover or and ex-prime minister.- anything where there is a possibility that they could one day again be a lover or prime minister.   $$$
(きゅう) Like 元 but there is no possibility of returning to their former state:the former Soviet Union. The older generations. The old version of software.
(じゅうらい) This is used about things or behaviors only. It means, “As it was done in the past.” “The old or traditional ways.”
(もと) Foundation or basis (the manga is based on the anime which was based on the videogame which was based on a true story).