Hi, I've been think a lot about who Zoah is/was supposed to be. Here I'll try to compile some info about him, and try to connect the dots.
As a starter, here is the infamous quote about Zoah from the developers:
"We might not be able to talk about the official game now, but there's a secret under Zoah's iron mask. It's said that his face was once injured in war and now he hides the wound with an iron mask, but in reality he's wearing it so as not to reveal his identity. Zoah's role was to be that of the prince of a certain country, secretly watching over the protagonists' doings from the beginning. If you had chosen the forest route (Slash Route) when it came time to infiltrate the Viper Room, you ought to have been able to see an event shedding light on Zoah's true identity."
And here is his character sheet info:
Full Name: Zoah
Occupation: One of the 4 Devas
Origin: El Nido
Age: 28
Species: Human
Home Time: 1020 A.D.
Home Area: Viper Manor
Height: 6'3"
Weight: 203 lbs.
Build: Mammoth
Hand: Right-Handed
Weapon Type: Glove
Innate Element: Yellow
Some speculations about him is here:
https://www.chronocompendium.com/Term/Zoah_(Planned_Identity_of).html, which includes information about connection to Guardia, and pondering whether Magus and Crono could be candidates of who he is.
If we assume that he has not done any time travelling, he would have been born in 992 AD. This means he'd be 8 years old during Chrono Trigger, and 13 years old when Porre invaded Guardia. Since he is possibly connected to Guardia and being a prince of some sort, that would mean he would be a brother or cousin of Marle somehow? Queen Aliza's death is approximated to be around 988 AD, but it could be a possibility that Queen Aliza died during childbirth? This would mean that he lived his childhood somewhere else, or was just not shown during Trigger. He would've come back to Guardia during the war in 1005 AD, and would've fought in the war (as a 13-year old) and got injured. Possibly he could've been the last defender using Masamune. This whole ordeal could have traumatized him, leading to his berserker angry loud voice, and making him use his fists instead of a weapon like a sword, since he failed with Masamune.
Another choice would be that he was an illegimate son of King Guardia XXXIII. He would've been sent to live in El Nido (or his mother being from there) because of the illegimitacy. Maybe he heard that his father is from Guardia (or even that he is the king!), and went to protect Guardia and gotten injured. From there on he'd decided that "AS FOR ME, I CHOOSE TO LIVE IN BATTLE AND ONE DAY TO DIE IN BATTLE.".
Another idea could be that he has somehow time travelled from 600 AD, got injured in the war there and got sent to the 1000 AD era somehow. His age leads me to think, that maybe he is somehow Cyrus? Maybe the statement that "Zoah's role was to be that of the prince of a certain country" means that maybe in some timeline the King at 600AD would've died and the Queen would have remarried with Cyrus, making him a prince somehow (similar to how the husband of Queen Elizabeth is a prince)? Cyrus got injured, got sent through time to El Nido sometime before 1020AD, and decided that he'd use his fists since he failed as a swordsman.
The idea that Zoah is Crono would work, if Crono was indeed the "last defender" in 1005AD when he was 23, got sent through time to 1015AD, where he decided to take the identity of Zoah and be one of the 4 Devas, while also similarly being traumatized and deciding he'd use his fists instead of a sword because of his failure (and also leading to pump iron and using growth hormones). Yellow innate could match Crono because of his lightning attacks. A similar scenario could work with Frog (=Glenn version) somehow (he was a frog prince in some timeline in the endings!).
Any other leads? Does anyone have skills to look at the Japanese original texts if there is some translation differences there or other clues?