◆ What happens when the cartridge battery runs out?
When the cartridge battery dies, the in-game clock stops progressing.
As a result, the “Auto Adventure” feature will no longer function.
※ In The Island of Revived Trials, the Auto Adventure feature was changed to complete instantly.
◆ What happens if you Reborn a Legend other than Hexa Dragon first?
If you Reborn a Legend other than Hexa Dragon first and then exit the menu with that Legend set as the leader, the game may become unplayable.
Normally, it is not possible to Reborn any Legend before Hexa Dragon, but in rare cases this can occur.
◆ Ranshiin (A) cannot be reborn properly!?
When Ranshiin (A) is reborn, it becomes “Michi no Legend” instead.
This was due to a defect in the manufacturing data, and at the time of release, Bandai’s customer support offered replacements if the Soul Doll was mailed to them.
◆ Manga version Greedo does not display correctly!?
The “Manga Version Greedo,” which was available as a mail-in bonus from Monthly Shonen Jump, appears as “Will-o’-the-Wisp” in the menu icon.
However, it is displayed correctly on the data and detail screens.
◆ How to obtain Doll Polish
In this title, the ways to obtain Doll Polish are limited.
・Sold at the Dwarf’s shop
・Dropped by Elves
◆ What does the “Favorite”（おきにいり） setting do?
When a Legend is marked as a “Favorite,”（おきにいり） its friendship level will no longer decrease, except when the doll is discarded.
Source
https://kako.5ch.net/test/read.cgi/handygame/1105456518