(Enjoy the meme)
So this is actually an informal rant so apologies if it's jumbled. As we all know Volume 11's bonus chapter for a lack of better words is fundamentally useless and doesn't give us any new information but that's about par for the course with these bonus chapters. However, I couldn't help but notice how indicative it is of the poor worldbuilding of The Underworld.
Lore Olympus's main setting is The Underworld - the domain of Hades, and the home of the deceased. It is also home to other deities and monsters, and because of this, it is known in Greek mythology as a perilous place that many Greek (and Roman) heroes have to endure on their journey. Dionysus, Heracles, Orpheus, Psyche, etc. are all known to have journeyed through the Underworld for various reasons in their own respective narratives. Bonus Chapter 11 introduces to a lesser known one (to the general public at least), the second kidnapping of Persephone. Well, attempted.
After kidnapping Helen (yes, that Helen), Theseus and Pirithous set off to the Underworld to kidnap Persephone. However, in doing so the two get stuck to rocks when taking a rest as punishment for their hubris. This happens as they see the Furies appear in front of them, so it can be assumed that this is a punishment enacted by the Furies themselves. Theseus is the only one who is freed (later, by Heracles) and Pirithous's punishment is to be devoured by Cerberus or is sometimes left ambiguous, assumingly stuck to the chair for eternity. Regardless, in the bonus chapter the two are punished directly by Hades and that's where it ends.
However, I couldn't help but feel that this chapter (amongst other things) reveals and is the epitome of everything wrong with the Underworld's depiction in Lore Olympus: it's empty. The two characters we see the most are obviously the King and Queen of the realm, but the Underworld would not be as terrifying as it is if it were not for the fact that it is inhabited by deities that embody death itself and the final judgement before you pass on. And it's not like Lore Olympus forgot to introduce some of these deities to us - Thanatos, The Furies, The Fates, Cerberus, etc. are established characters in the world of Lore Olympus.
Yet, we never see these individuals do anything of substance that would convince me that the Underworld is as thriving and terrifying as Rachels sets it up to be. The overfocus on Hades and Persephone's Girlboss Y/N x Scary CEO Daddy dynamic completely overshadows the deities that make the Underworld as daunting as it's supposed to be. They end up being supporting characters in the worst way possible (as in, they literally enable the worst behaviors in the aforementioned main characters ) and it ends up making the world feel more empty than it should. There is no real reason given in universe as to why the Underworld is as well off as it is. And the complete absence or inaction of significant figures like Charon, Styx, the Cocytus river (of which Minthe is a daughter of in mythology), and even lesser known rivers/bodies of water that contribute to shades' lack of autonomy (Lethe and Mnemosyne), etc. contribute to this empty feeling in the webcomic.
So when Theseus and Pirithous arrive in the Underworld in this bonus chapter, there is a clear lack of struggle or evidence of a struggle to have even reached Persephone. It truly does feel like in Lore Olympus, anyone can indeed just walk into the Underworld with very little problem. There's no pushback towards trespassers unless you assumingly set off Persephone, who can simply call on Daddy Hades to deal with her problems for her. Because not even the literal Queen of the Underworld can be set up as a terrifying presence in a comic about her (unless you are lower class, of course). Fundamentally, the Underworld functions as a status symbol for Hades and Persephone's "divine right" as King and Queen, and less of an afterlife for mortals or place of punishment for those who transgress the Gods. Elysium has been talked to death here so I'll spare making this rant any longer than it needs to be but it's very clear that the Underworld in Lore Olympus is about as useless as this chapter was.