What happened to Mieu?

Alternately, the Wren series is a modular design designed to incorporate many different kinds of parts. Both 3-Wren and 4-Wren end up getting three sets of upgrade parts, it's just one spends it all on mobility and the other spends all his slots on guns.

The bottom line is that PS3 Wren is "Searren" and PS4 Wren is "Forren;" these are the names in the Japanese versions. ( Interestingly enough the "Searre" of Searren is a cognate of the term "three" and the "Forre" of Forren, is of course a cognate of the term "four," as in Phantasy Star Three and Four.

The only other thing to mention is a correction of dates:

PS1: 342
PS2: 1284/85
Dvastation ( Orakio/Laya/ Dark Force) War: 1284+1000=2284
PS3: 1284+2000= 3284
PS4: 2284

The only reason why its less than 1000 years between PS1 and PS2 is because Palma was destroyed, which was part of the "seal" that The Great Light placed on the Profound Darkness.

Zio_Falz : thank you so much about all those explanations ! And all about the different dates