>>714248556 (OP)Like the nature of Elden Ring itself, the foundation of the Erdtree and Golden Order over the preceding civilisations, and the respective births of Marika's various demigod issue, is a very murky aspect of the lore, and the largely unsubstantiated timeline can only be pieced together and roughly assumed from scraps.
Messmer and Melina appear to be the earliest of these children, with Messmer being described as an elder brother/avuncular figure to Radahn. Ostensibly, you'd assume Radagon was Messmer's father, simply due to the shared red-hair motif and self-hatred, alongside the OST similarities, but Messmer seems to have been born prior to Radagon/Marika's unification, and bears a serpentine curse pointing to an altogether different origin.
Godfrey's issue seem to be next in line, with the omen twins Mohg and Morgott, and Godwyn the Golden.
Then came Radagon's children with Rennala, and finally Malenia and Miquella post-convergence.
In between the splintering of these lineages, you have the campaign against the giants with Godfrey, the slaying of the Storm Lord and the seizure of Stormveil, Godwyn's routing of the Dragons, the appearance of Radagon and the Liurnian Wars, the banishment of the Nox, and the extirpation of the Hornsent and obscuration of Enir-Ilim. You'd think the DLC might have occured at a primordial time long before any of these events, but it's filled with characters and references to times and events that seem to taken place in the near past with Radahn and Gaius learning gravity magic at Sellia.
The Elden Ring, as it visibly shimmers in Radagon's fractured chest cavity, and manifested in the form of the Elden Beast, appears to be just as much an incarnation of the metaphysical code of the Greater Will, as it is an actual physical entity.
Personally I strongly believe that Messmer might actually be Radagon in some shape or form