The Magic team is very good at creating the illusion that there is a world beyond those walls, but D&D players need to be able to go there, in ways that the card set doesn't.

[20] In 2017, Mike Mearls wrote: "It's basically a thing James does for fun, and we don't want to burden it with needing all the work required to make it official".

This has disappointed fans greatly, as some very popular characters appeared in Theros Beyond Death and players bemoaned missing the chance to learn more about them.

[23] WizKids released a set of 45 Mythic Odysseys of Theros themed Dungeons & Dragons miniatures as part of their Icons of the Realm blind box line.

[27] Gavin Sheehan, for Bleeding Cool, reported that the timing of book's publication, between Critical Role's sourcebook and the COVID-19 pandemic, meant that Mythic Odysseys Of Theros "got passed over in a lot of eyes" especially since by the time of the D&D Live 2020 event the focus had shifted to the new adventure book Icewind Dale: Rime Of The Frostmaiden.

[...] I particularly love the way the book incorporates the flavor of the gods themselves in their individual chapters, including examples of myths the folk of Theros might have about them.

[29] Simon Yule, for GeekDad, wrote "Fans of Magic The Gathering will recognize this new setting, as Mythic Odysseys of Theros comes straight from WotC’s other main product line.

But don’t worry: those slightly worn-out jeans and unwanted, stained Converse All-Stars can find a new lease of life as second hand treasure".

Each of these creatures has Mythic Traits and Actions which the Dungeon Master can use to ramp up the difficulty and really hammer home the sense of a truly terrifying and world-ending threat".