I have a lot of thoughts on Omegaverse in fgo, so here are all my thoughts in one post, hopefully it will not end up too cluttered.
Guda is an omega. Omegas are usually characterized as the “"weak”“ lads whose strong traits are being caring and motherly or whatnot. Guda, who has no real skill on their own aside from being friend-shaped, would qualify.
Guda is a beta. Guda is ultimately Just Some Dude, and being the one omegaverse alignment no one cares about would reflect that. Additionally, being an alpha or an omega gives you magecraft buffs, so Guda being a beta would also highlights that magic isn’t their strong suit.
Guda is an alpha. See: the omega entry, I think it would be an interesting subversion of the trope to have the one guy whose defining character trait is "cares about the bitches around them” to be an alpha. Additionally, alphas are usually characterized as the leaders, and in a way that’s kinda their job as a master.
Guda is whatever the omegaverse equivalent of trans is. I have nothing witty to say about themes and symbolisms, I just think there should be more trans omegaverse stories so I wanted to include the option.
Guda is none of the above. Having a secondary gender is exclusive to mages (it’s a side-effect of passing the magic crest through too many generations) and Guda’s pedigree is too recent and/or shitty for that to be a thing. Goredolf taking Guda by the shoulders saying hey, your files didn’t say anything about it, but I want you to know even with limited ressources we’ll do our best to accomodate to whatever your needs are, just tell us when your heats or ruts usually fall and we’ll plan accordingly. And Guda is just. My fucking what now.
Command Spells are basically like using your alpha voice ™ on people, so they basically put you on magic alpha HRT. It doesn’t normally do much because holy grail wars last for like, a week, but in Guda’s case it’s been so long it’s now severely affecting them. Congratulation on Ritsuka Fujimaru and their unique hormone cocktail in the entire history of humanity. Poor lad spends a week being weirdly emotional over the weirdest shit until the medical gang realize they’re teething from their second/third puberty.