This is yet another Mutate commander in Ikoria. It's Ultimatum is amazing. It's enchantment is all right.
Ikoria has some solid Menace support for this deck. Mardu is all about combat.
Ikoria has a strong Humans component, and also a Human friends component, with the minor caveat that Mutate creatures cannot interact with Humans.
Cycling works well with the Human theme in Ikoria.
And since Cycling drops cards in your graveyard, it will not hurt to have cards that profit from what you drop in your grveyard.
There are also some cool Red exile cards in Ikoria. This theme is all about temporary exile and casting from exile.
The Mythos for this wedge is a Balance-type of card.
Kumoros, like most of Theros II, is the card that could have been great. It fits a very narrow deck in these colors. "Players can't case spells from graveyards" is a great clause in every other possible card but this one. Theros II, what were you thinking????! The devotion set without devotion, and the graveyard set with neutered graveyard interactions. It's great for a set to be so well-balanced that it has no broken cards. It is also true that a well-balanced set can balance itself out of fun, and Theros II succeeds brilliantly in this department.