I always saw it as IV -> I -> II -> III -> V
Ryu removes immortality from the Endless, in turn creating the Dragonbrood
Deis is given physical form by Yuna
Myria is called into the world by Yuna
The Dragonbrood split into two factions (One allying with the summoner who says Myria can impart immortality, and one choosing to respect Ryu's wishes) and eventually, the Warrior of the Dragon puts an end to it
Zog, leading the Dark Dragonbrood starts trying to awaken Myria again to unite the two factions under his rule
Myria is sealed once more, but she leaves behind Deathevan
The next descendant of Ryu fights him back and seals him away
Myria is brought back into the world by the scientists of Caer Xhan and tries her hand as a ruler, only for it to end horribly when she orders the extermination of the Dragonbrood
Still, Myria sends technology to in order to sate the remaining humans
The remaining Dragonbrood go into hiding, giving up their powers (With only Ryu remaining)
Myria is once and for all defeated, Deis going with her
Mankind figures out how to work and repair the machines on their own power, discovers electricity (Jolt spells probably helped, LOL), and thrives for a time
A war breaks out over the usual human desire for greed and conquest, and bioengineered war machines resembling the Dragons of old are made to wage it
The world goes scorched earth; the remaining inhabitants are forced underground
BoFV backstory here (I got lazy)