Talk:Lost World (card)/@comment-25521923-20180810155433/@comment-36375292-20180810161617

"You cannot choose "Lost World" as your initial flag, and you may put up to two of this card into your deck in all flags and use it."

A face-down flag is still a flag. Hence, why Omni Lords can still be used. As well as other cards (like Garga) that can be used under any/all flags.