I found some secret texts in Phantasy Star III and share it here.
I was able to display every text in the game available in the ROM except one but was able to finally find it at the very beginning of the game...
No, not this one!

This one! (retranslated version from japanese)
https://www.romhacking.net/translations/3549/

And the same one! (official US and Japanese versions)

おまえには、 とないの くにの ひめと けっこんさせようと おもったが ・・・
Who is talking ? Could it be Lyle ?
Perhaps he has the ability to make himself invisible to hide in the castle, as well as the ability to transform into a dragon.
What do you thing about it ?
If we look at https://phantasystar.fandom.com/wiki/Lyle, it says that in the Unofficial Doujinshi, Lyle's ability is to shape shift.
It says that : « although he commonly transforms into a dragon, it is perhaps not the only shape he can assume. »
So maybe we are talking to Lyle in a little butterfly form nearly invisible, after all...
Edit : Thanks to Hugues (https://huguesjohnson.com/), I found the dialogues I was missing in the city of Lashute. You have to get there before getting Orakio's Black Sword.

