Zeus’s final form is Zeus’s final physical appearance before being destroyed by Athame. Zeus takes on this appearance at the end of the Belrock Arc, after merging with Ryan’s body. The significance of it is to serve as a wake-up call for virtually every character, causing them to realize that Zeus is becoming something that has to be dealt with soon of they’ll be serious consequences. It quickly becomes too late when Jure secures Zeus’s safety.
Zeus’s body became grotesque and purple in color. He no longer has any apparent skin tissue, and his body becomes laced throughout by blood vessels, all of which twitch to an irregular heartbeat. Soon, however, the blood vessels begin to burst as the parts of Zeus’s body exposed to the air become inflamed and swollen. Zeus then looks like he’s one big broken pipe, expelling blood like a lawn sprinkler. Soon his body becomes drenched in his own blood, and his purple body becomes dyed red. As he stands in a puddle of blood, soon the blood on his body begins to darken and crystalize, forming a kind of scab. When Zeus finally settles, he has a suit of armor made out of his own blood.
Looking into his eyes causes people to take a step back. The very sight of his blonde hair and blue eyes gives you the overwhelming sense to believe that his self-righteousness is gospel. That it is for some reason morally wrong to not let Zeus get what he wants. That you’re the evil one here. It doesn’t matter that he’s a hideous, nauseatingly ugly creature, and it doesn’t matter that he has and is willing to commit countless atrocities openly. Everyone is willing to forgive him, and so do you. When you take a close look at him, you realize you’ve never met another man who believes in himself quite nearly as Zeus does. You just happen to find it… inspiring… indomitable even. Also, being near Zeus causes one to hear a sound similar to high-voltage power lines. The sound is mad-driving. It claws at your mind and eventually you can’t help but plead for the awful sound to go away. Some people are driven to the point where their minds convince them to follow Zeus with unquestioned loyalty, usually against all logic. If Zeus rejects them or otherwise, he can make powerful shockwaves of noise that are so terrible, even the maddened people start hurting themselves just to make the sound go away. They tear their faces off, smash their heads into iron, or force their brains to explode. Anyone who dies in Zeus’s presence, anyone, can be claimed by Zeus, which basically means they become a zombie (really just an Astatos) subservient to him. For the plotline of Timelord.odt, Zeus has a reason to want to appear in places of mass conflict, acting with the intentions of a graverobber. It’s intended that in the final battle against Zeus, he has an army consisting of every character that died during the time of Timelord.odt as monsters that fight on his side. This includes characters such as all the Dualics and N.D.S Soldiers that died within war, Nexandra, and Serken’s wife Agatha. Additionally, those that can sustain the maddening static within one’s each ears have to watch as Zeus revives those that have fallen on the battlefield in the very fight against his army.
If Zeus kills a person’s family, the sole surviving member may come after him with controllable anger. However, looking at Zeus as said in the above may cause them to stop and then realize: “Wait, I am the chosen one!” And all of a sudden through away all that anger and serve Zeus. Zeus definitely doesn’t care for that person’s life though and would cast that person aside without a second thought. Zeus also probably doesn’t realize that he has a supernatural aura around him that causes people to go crazy. He probably thinks that these people just happen to see reason.
A Hybolian is technically a fusion of a physical body and an incorporal spirit. Zeus doesn’t have a physical body until he takes Ryan for his own, but Zeus is not actually a spirit, nor is he a Hybolian either. Instead, Zeus is an Astatos—an abomination that happens when something goes in-between the concepts of body and spirit. Another way of putting it is when a Hybolian tries to become a body-spirit, but something goes horribly wrong. Either way, Zeus wants to re-complete himself and become Hybolian, but because he’s an abomination, it isn’t a question of simply finding spare parts to put himself back together—it isn’t possible to re-complete himself. However, this is what he tries to do. As a result, the more he attempts to tamper with his corporeal/incorporeal body, the more warped he becomes. He gains body parts where you shouldn’t have body parts and the ilk. Merging himself with Ryan’s body doesn’t make things better, but rather it makes everything a lot worse.
Zeus left Ryan’s spirit left for dead after he seized his body. Zeus’s presence and aggressive behavior towards it caused the soul to corrupt and become Astatos as well, leaving Ryan in a very similar position to Zeus. Erica was created when Ryan’s spirit regained a new consciousness. Erica posses the memories of Ryan, the knowledge and wisdom of Zeus, the powers of both, and the mind of a girl that was supposed to reincarnate from Ryan’s soul 500 years in the future (Erica also knows the entire timeline of the girl she was supposed to be. Who her friends were supposed to be, what kind of household this girl was supposed to grow up in, etc.) The tampering of one’s conscious is common for Astatos, particularly across incarnations of one’s soul. As Zeus was a primeval Hybolian, he was unaffected by this and simply driven insane—or was he driven insane? Maybe he was insane to begin with? Who knows.
In his time in Ameniah, Zeus’s pursuit of power and body parts had left many hundred civilians affected, all of which corrupted into Astatos in need of “replacement parts”. Since an Astatos remains an Astatos even after it takes parts from another (it can’t re-complete itself just like Zeus), but creates another Astatos in the process, it leaves the potential for corruption to spread across everyone like a zombie plague. However, the insatiable desire to restabilize oneself (The desire to find “replacement parts” for oneself, even though it doesn’t work) is common among Astatos. Only Deondavra can fix someone once they’ve become an Astatos. That’s why he has agents to search for and bring him anyone who’s become one, so he can decorrupt them (This results in a Demon Soul).
Zeus’s goal is regain the status he had before he was trapped in the amulets and had himself warped. Effectively, Zeus’s story is similar to that of a riches-to-rags millionaire who lost it all, and while Zeus sulks on the streets moping, he plots to regain it all back. He was a great man of high status, and this makes him think he’s privileged and entitled, stepping over people without thought. Zeus is not stupid though, and probably knows of his fate even since the beginning of the story—once you become an Astatos, the two ways you stop being one is if your existence is revoked or if you’re turned into a Demon Soul, and both of them effectively mean death (Becoming a Demon Soul will force the soul to take on a new consciousness much like how Ryan was forced into becoming Erica.) Zeus is too proud to let himself die, but he knows that most Hybolians will see him as something that needs to be taken care of—something that needs to be either destroyed or receive Deondavra’s treatment. That would force him to lay low until he can establish a foothold—something that can ensure his own safety. Additionally, Zeus can’t manipulate Alpha like Hybolians can, which means he can’t leave to Niag even if he wanted to. It doesn’t seem like a wise decision because Niag is ground zero from Hybolian activity. Additionally, I informally consider Zeus too spirit-like to be able to set foot in Niag until at least he reaches final form—perhaps even then, he is not yet ready (Niag is strictly a mortal plane and spirits can’t exist much like they can’t in the real world. Spirits can only exist by themselves within Auxe and Nethia and the further up in Nethia you go, the less of a presence Spirits have.)
Athame is the only person in Ameniah or Jugenoir that has any form of responsibility for taking down Zeus or people like Zeus or other Astatos, and that one is a moral responsibility—not one that can be punished. No one is there to force her, which means getting rid of him is a choice she has to make herself, and will she? Athame knows better than making the assumption that Zeus is harmless, and that if he isn’t handled it could mean an apocalypse. To say the least, Athame puts it off and waits for other people to handle it. It’s likely that the King Spirits all play a role in attempting to bring down Zeus, but I would say Zeus is very capable of taking them on 1v1, especially in Zeus’s later stages. As Zeus and Athame have encountered each other several times, Zeus likely knows that she isn’t interested in being his bounty hunter. That means that Zeus has a favorable environment to set up shop, because she will let him do as he pleases. He will take advantage of her nature as much as he can, because it’s life or death for him. On the other hand Athame definitely looks down on him. Sees him as little more than a boyscout playing a game of scavenger hunt. Athame likes to laugh at people for how small and transparent they are, and Zeus is definitely her newest punchline. There isn’t any way she could have known Jure would swear allegiance to him, because while Athame informally knew who Jure was, she would never have known Zeus’s background. Athame was born millennia before Zeus’s time, and even if she was informed, it’s not like she would’ve cared who he was. Athame doesn’t care who anyone is, and even after that, she’d have to remember that information for yet another millennia. Athame was also likely assuming that if she didn’t take care of Zeus, Deondavra would send someone to do it when he became aware that something was wrong. And he did, and that was Jure. This combination of Athame’s passivity and meeting Jure of all people is incredibly lucky for Zeus, no doubt, but it’s powerful fuel for the plotline Timelord.odt’s main villain, and a huge boost to Zeus’s ego—he probably thinks it happens because he’s just that good.
If you ask me, the main reason why Zeus does so much damage in the end is because of the Amulet children—Ace, Duke, and Kris. Ignoring the fact that they caused Zeus to appear, had they been more proactive when dealing with Zeus, they could have done a lot to have stopped his reign of terror, rather than let everyone else handle it; The Amulet Children were the first in the line of people to say: “Someone else will handle it.” However, the children were not wrong to think that. The U.D.S implied that there were to take everything out of their hands, and Zeus mostly left the kids alone. The only motivation that for going after Zeus would be to play the role of hero, and although they’re the main protagonists, that’s just not how they roll. They’re just kids, and kids are not very responsible.