Hi this is a very random question with probs no answer but I wanted to see your opinions on it. Who do you think is castor and pollux’s mother/other parent? (Mr D’s kids not the actual mythological figures lol) Cause the main options that me and my friends came up with is that either they were someone who some how came to the camp (specifically not a camper but idk how’d they’d get there) Or they were a camper. Either way Mr D isn’t supposed to leave the camp, so how can he have kids?

(I’m not asking if you think they’re a specific character more so who would their other parent be if that makes sense lol)

So one of the established things in the canon of how deities work - at least the Greco-Roman deities - in PJO is that they can inhabit multiple spaces at once, which is very interesting. We’ve seen this a couple of times in varying forms (less so as the series goes on), in fact primarily from Dionysus. The best moment I can think of off the top of my head in-series that explains this is in TLO, where Percy talks to Dionysus while Dionysus is at a party and he explains how he can manifest at least partially present in either a physical or non-physical form in places relevant to his aspects - in this case, revelry. Mr. D, as camp director, is almost entirely present and locked to CHB, but he is capable of also partially not being there, because he does still have godly duties to attend to in bits and pieces in places where his aspects are present. So, theoretically, we can presume a situation such as that is how Dionysus had Pollux and Castor. (This also plays into my personal headcanons about demigods being primarily born of specific epithets of their parents - as presumably the partial-presence thing would result in only specific aspects of that deity being present to specific things - resulting in a specific range of potential powers depending on which epithet they’re born from, i.e.: Meg being born from an older form of Demeter.)

Though I do also like your idea of Castor and Pollux’s mortal parent potentially being a mortal who visited camp, because we actually have a couple of different routes you could go with that. First is obviously, parent of an existing demigod at CHB, which is kind of a really funny option to me because this means Castor and Pollux potentially have (or had) an older half-sibling with a different godly parent. That also actually fits the myth of the original Castor and Pollux well because depending on the version of the myth they actually had separate fathers despite being twins (or, also depending on myth, actually quadruplets with twin sisters Helen of Troy and Clytemnestra). Heck, if we want to go more in on the myth paralleling, maybe Castor and Pollux are quadruplets and have or had twin sisters in camp in a different cabin, and their parent had come to camp before actually having their kids to get advice beforehand from Chiron. I actually really like that headcanon now. Dang.

Other options are the “mortal ended up in camp not knowing anything about demigods” routes - and we have two potential routes I can see for this. One being the Lost Pizza Guy™ route of “A deity purposefully summoned a random mortal to camp for Reasons and let them in,” second is actually acknowledging that CHB is, to mortals who cannot see through the mist, disguised as a strawberry farm that is publicly known and theoretically occasionally receives mortal visitors (by accident or on purpose) which is also interesting because in TOA we’re actually told that CHB is surrounded by other farms. Maybe it was people from a neighboring farm visiting, or mortals who wanted to tour and/or go strawberry picking, both of which do actually align with Dionysus’ aspects as an agricultural deity, which is also potentially pretty cute cause that implies Castor and Pollux’s mortal family is most likely local and that Castor and Pollux might have grown up around camp if not actually lived right next to it.

Anyways, options abound! Thank you for leading me down this train of thought because now I have significantly more Castor & Pollux thoughts and they’re all very cute. These are all delightful options.