WARNING: The following contains spoilers for Ghost Rider: Kushala #4, available now on Marvel Unlimited.
Having honed his already-impressive intellect to near-superhuman levels and mastered almost every field of art and science known to man, one would think that Dr. Doom would find contentment in the fact that he has proven himself to be one of the most intelligent people on Earth. However, Doom's desire for knowledge is as insatiable as it is ambitious, and there are still a few things that the tyrant does not know.
Many mysteries continue to plague Doom, but Ghost Rider: Kushala #4 (by Taboo, B. Earl, Guillermo Sanna, Vanesa R. Del Rey, Jordie Bellaire, and VC's Joe Sabino) has not only revealed which one vexes the Latverian dictator the most but how he intends to solve it. Having learned every lesson that the universe has to teach him, Dr. Doom has set his sights on unraveling the complex formula of cause and effect that creates the many alternate universes that make up the multiverse, a mystery he could not solve even when he was omnipotent.
Although many Marvel characters have channeled god-like power through artifacts like Dr. Strange's Eye of Agamoto or Thanos' Infinity Gauntlet, Dr. Doom holds the unique honor of having become a god-like being himself on several occasions. The first occurred in the original Secret Wars (by Jim Shooter, Mike Zeck, and Bob Layton), when the Beyonder, a cosmic entity who had developed an interest in Earth, brought Doom and several other heroes and villains to the patchwork planet of Battleworld and pitted them against one another. Refusing to be the Beyonder's plaything, Doom bided his time until he saw an opportunity to attack the cosmic entity and gain his power for himself. Although Doom quickly lost his new powers, he did manage to seemingly kill all of the assembled heroes in the brief time he possessed them.
Years later, in 2015's Secret Wars (by Jonathan Hickman and Esad Ribic), Doom once again achieved omnipotence by absorbing the powers of all of the Beyonders, who were trying to destroy the multiverse. Although Doom used his new powers to save the multiverse by merging its shattered remains into a new Battleworld, he also took over the planet, taking the title of "God Emperor Doom" and using his cosmic abilities to subdue all who opposed his rule. In the end, it took a coalition of some of the Marvel universe's most powerful heroes, villains, and cosmic forces to weaken God Emperor Doom to the point where the Beyonders' powers could be siphoned out of him, restoring the multiverse and ending the divine despot's short-lived rule over reality.
Since then, Doom has moved on to other endeavors, but the mysteries of the multiverse have continued to frustrate him. In Ghost Rider: Kushala, Doom sets out to solve the riddle of the multiverse once and for all by assembling the Wands of Watoomb, magical artifacts tied to the very fabric of the multiverse. To achieve this, he also requires the descendants of Kushala, the Apache Spirit Rider, who hold the key to locating the sixth and final Wand. When speaking to Liam Cameron, the Latverian agent who spied on Kushala's descendent Oliva Obtera, Doom admits that he was unable to solve his questions about the multiverse while he was God Emperor Doom, as its workings were too complex for even a god to make sense out of. But by using the Wands of Watoomb, Doom hopes to finally unlock the multiverse's greatest secrets and solve the formula needed to create the perfect Earth, even if it means kidnapping Olivia's young daughter Heather Rae.
Dr. Doom's admission to Liam offers a unique insight into the mind of one of Marvel's most reserved supervillains. Although Doom has always carried himself with an intense aura of confidence, it's clear that his failure to comprehend the complexities of the multiverse has harmed his otherwise unflinching resolve. As a man who holds his intellectual achievements in high regard, Doom's inability to understand the multiverse's inner workings has been haunting him since the reign of God Emperor Doom came to an end.