Fire Emblem codenames suggests another game was in the works after Three Houses

A Fire Emblem fan has recently been looking at the internal codenames for previous entries in the series and has discovered that there is potentially another Fire Emblem game in development at Intelligent Systems that was being worked on after Fire Emblem Three Houses development was wrapped up. Fire Emblem Three Houses was known internally at Intelligent Systems as Iron17 and Fire Emblem Engage was known internally as Iron19, so that just leaves Iron18. It is thought that Iron18 could well be Fire Emblem Genealogy, which has been rumoured as being in development at Intelligent Systems for quite some time.