It could be something as simple as just in-game mechanics. Rather than recreate sprites and animations, its alot easier to simply recolor a set, especially if the recolor holds a similar 'value' to the player/gameplay. Those playing Trigger for the first time facing off against Masa and Mune will fine them a challenging fight, and when it comes time to fight Spekkio in that form, its a similar challenge that's scaled up to compensate for the characters increased powers and stats.
Spekkio does seem to be familar with the various time streams, as he's able to identify that particular element of each character, or at least identify that based on person's affinity for magic (like ayla having none, therefore she's ancient) That aspect might simple be part of the nature of residing in the ends of time, you simply are able to observe things.
Now Spekkio's claim to God of War could either simply be self proclaimed, or actually gained from a lifetime. If he is a creation of Zeal, then perhaps before the time of the Zealean royal family, there were wars waged, and with the aid of the guru's/spekkio Zeal grew to power. Wayhaps Spekkio was the Cryrus of King Zeal? And wayhaps he was killed in said war, as I don't think they specify how he died, they just include that he is dead. A major distinction in class basis among a common set of people could have resulted from previous wars. That would certainly account for the docility and poverty of the earthbound ones. If the dreamstone incites love and hate, certainly that alone can be reason for war, and Zeal does have the dreamstone, while the earthbound ones don't.
