The important thing to remember about Overshadow isn't just that he's one of the greatest magicians in the world and one of the world's greatest terrorist leaders. That he, honestly, believes he's the most powerful and brilliant man in the world. It's the fact that he's been sitting in a dark underground chamber for the past sixty years while being surrounded by utter sycophants. That means that Overshadow is really living in an entire world all his own.
While an extremely competent villain, a lot of his plans are based around faulty premises because he's so utterly out of touch with modern reality. For example, he honestly believes a weather satellite threatening the world might cause the entire planet to capitulate to him or that its possible for the Earth to survive nuclear warfare because all of the information he has is delivered by eight layers of bureaucracy.
Overshadow also spends way too much time contemplating what he's going to do when he rules the planet. His lair is filled with models of renamed cities, plans for an Overshadow Statue replacing the one in the harbor, and putting his face on the money. The fact these plans never see fruitation actually causes him to enforce them inside his bunker. I.e. agents of Shadow often find themselves forced to use the Overshadow money in their bases.
One final thing is that Overshadow is simultaneously desperately lonely and aware on some level that he's still essentially fighting WW2 from the position of Hitler in the last days. He, unlike many villains, will actually keep captured characters alive because they're the only people in the world in a sensible manner that he can talk to without puncturing his aura of invincibility. While he's protected himself from betrayal by his clone minions, the whole purpose of power (in Overshadow's mind at least) is the prestige of power and to impress others. Impressing a clone that one built to serve you or his mercenaries is rather unsatisfying.
To this end, most who interact with Overshadow find him also ridiculously gracious for a man holding them captive. Often being held in luxury quarters when not in specialized holding cells to witness his triumphs. He brushes off his Nazi past and instead points out that the New World Order will be beneficial for all. He makes up a ridiculous 'code of honor' that he claims to follow in order to allow him the occasional grand gesture to impress his prisoners. He's occasionally let heroes go deliberately when they're interfering with a minor operation in order to spread reports of his grandeur. While no one can be acknowledged as his equal, superheroes are usually the only people that he can think of as peers.
Despite his best efforts to believe that THIS time, the world will fall to its knees...Overshadow is frankly getting sick of it. The world has changed since the 1940s let alone Ancient Egypt. Previous generations were much more easier to intimidate thanks to the lack of superheroes and the world being less intristically entwined. On a fundamental level, he knows that SHADOW is an organization that many people hold in contempt and enforcing his will over the populous through conventional arms is impossible. This is why he's experimented with such ridiculously grandiose methods as worldwide mind control and rewriting world history.
Overshadow is now, for the first time in decades, honestly considering abandoning his current enterprise. While he is loathe to give up any form of power, it's not that difficult for him to believe his minions are hopelessly incompetent. With control over his cycle of immortality, he's considering that it might be a better idea to take a vacation away from it all then start over. Some spectacular destruction that puts an end to SHADOW as it currently exists.
Frankly, if he wasn't guilty of war crimes to a level unimaginable in the world, then Overshadow probably would have surrendered long ago to start building a legitimate power base again. One based on modern ideals of corporate dominance or manipulation of current leaders from behind the scenes. While he longs for the day of the God Kings of old, being actually able to interact with with the elite again would be deeply satisfying.
Another part of him is actually contemplating abandoning the dream of world domination for a few centuries. Magic was always a tool to Overshadow but he's gradually begun to find more satisfaction in increasing his vast knowledge than he is in lording over minions. This is actually a transformation that occurs to many magicians, usually much sooner than Overshadow. The allure of the arcane might actually end up drawing the evil magician from his current plans. What is dominance of one astral plane after all versus the power to make reality at ones will?
Kal-Zed comes from a hyper-advanced civilization and his knowledge of Ultimen technology has given him the reputation as a super scientist and military genius. The irony is that he's only slightly above average intelligence and lets his emotions guide the majority of his decisions. Kal-Zed fancies himself a modern day Caesar (or the Ultimen equivalent) but he's actually closer to Mark Anthony in that he gets by on brute force in most cases.
Unlike Overshadow, Kal-Zed hasn't had the polish wear off his numerous struggles with the Centurion, AEGIS, or the former Allies. Despite the fact he's been fighting for forty years, its still the time of his life. The fact that he had no real sentimental attachment to the Third Reich and won countless battles made their defeat to be something of an academic struggle to him rather than a crushing one.
What Kal-Zed is really after from his struggles is enterainment. War is tremendously fun for Kal-Zed because he's in no real danger from his numerous battles with him. The Centurions avowed respect for life and his own invulnerable body has made threats against him to be almost pointless. The fact that his soldiers frequently look at him as a God when he rushes in and starts smashing everything is enough to make it even more fun. One rather infamous quote is a good summary for how he views his actions....
"Those who say war isn't a game are fooling themselves. Bodies are how you keep score."
This attitude has colored his actions since the fall of the Third Reich. His joining with SHADOW was an easy way of aquiring soldiers to continue his war games but his revolts have always been out of a pathological inability to obey orders (and Overshadows unwillingness to flatter Kal-Zed at every step of the way like Hitler did). Invariably, Kal-Zed finds the actual process of leading an army to be tedious and either reconciles with Overshadow or leads them in one last glorious stand that probably levels a city.
This utter incompetence as a ruler as opposed to a military commander or inspirational leader is pretty much unknown to his troopers as he certainly talks a good game. Highly charismatic, he gets by on jingoism and talk of superiority with more than a few soundbytes being directly lifted from Hitler. Honestly, Kal-Zed is smart enough to keep his public satisfied by throwing them bones but is like many a celebrity in that he's fairly disdainful of them in private.
In addition to being a murderous psychopath, an unimaginable egotist, and so self absorbed by his pleasures that he can't be bothered to rule....he's also an intolerable lech. Superior's underwear model good looks means he has very little difficulty in enticing women into his bed but he's honestly never bothered with whether they're willing or not. Superior has a particular fantasy about superheroic women and those he wouldn't have to "hold back on." It's a threat that has made him particularly repulsive to Lady Liberty whom once hospitalized him in a rage after he'd made the threat (and nearly crippled her husband). That actually increased his attraction but he was banished to another dimension before he could come back for seconds.
The organization of SHADOW is currently crumbling around the edges and it reflects their masters own ambivalence towards it. The organization is, ostenibly, more powerful than its ever been in its history but it is also fractured in several irrepairable ways.
The original Shadow members were expatriate Nazis, Japanese, Italians, and their sympathizers that were plotting a reviving of the Third Reich. Hitler Youth were kidnapped from their homes before being infiltrated into the United States and Allied powers to prepare to corrupt the enemy from within. They were highly motivated and extremely successful but the overt Nazism of many was enough to have many operations foiled.
It was Overshadow who started the initial cracks in the organization when he decided to ally with communist hardliners and allow them into the ranks. In addition to the distaste of many National Socialists towards communists, there was also the fact that Overshadow had no problem with including ambitious Chinese agents who wanted to advance their own cause in the turbulent climate under Mao. His abandonment of racial superiority resulted in several attempts to overthrow him.
The most famous of these factions was ULTI-SHADOW which was the American Branch of SHADOW that was taken over by Superior. While more famous for his battles with the Centurion, Superior laughed at attempts to infiltrate the United States when he fully intended his own revolution. Overshadow and Superior oddly would battle then reunite their forces on several occasions as the two reestablished pecking order between them. Superior has always been very much a child despite his super genius and Overshadow usually was the victor of these conflicts.
There's still a good deal of sympathy with him since Superior has ever been more charismatic than Overshadow and approachable. Unlike Overshadow, Superior has little fear from his subordinates because he's blind to the idea that anyone can betray him despite several notable incidents. He rewards graciously his men with plunder and recreation while acting as a front line soldier. This has always been the chief reason the Supreme Kommandant has always been the chief danger to Overshadow.
Their conflict also lead to the creation of INNER SHADOW which was where the majority of Overshadow's private staff was replaced with clones or the utterly brainwashed. Inner Shadow remains the idealogical heart of Shadow but the near mindless soldiers have no initiative but what their leader orders them to but he is badly out of touch with reality. Nevertheless, few of the other branches are willing to breathe without Inner Shadow's approval as the clone troopers will kill anyone who defies Overshadow's will or a directive even when said directives are wrong.
TENDRIL is a branch of Shadow that is probably the most dissatisfied with the current handling of the situation. The financial branch of SHADOW, it is recruited primarily from young and intelligent entrepreneurs with no scruples that want the help of the terrorist organization in spreading their influence/becoming wealthy. Unfortunately, once one has succeeded, they become little more than a cash cow for Overshadow's plots and there is no dissent tolerated. Superior loathed tendril every bit as much as Overshadow dismissed them as merchants. The Labyrinth has simultaneously a great desire to dismantle Tendril as one of the few threats to its size and the idea of possibly making a break from it to their organization. The Minotaur has no desire to start a war with Shadow though.
The other divisions like SECRET SHADOW the occult division, simultaneously in awe of Overshadow and frustrated they aren't the chief group, and SHADOWTECH the R&D division are also kept out of the loop when they feel that they are not recieving the respect they deserve. Given they're all psychotic lunatics with delusions of grandeur, this is unsurprising but doesn't really help morale. They often seek to subvert Inner Shadow or push their own agendas to impress Overshadow. Ironically, this only makes them threats in his eyes.
Finally, the best soldiers of SHADOW are usually mercenaries and killers recruited into the lower ranks and set to guarding unimportant facilities in lieu of Shadow clones. Ironically, this makes them the most dangerous as they are capable if independent thinking and often have extremely powerful "toys" as part of their ability. It's a great risk to employ them instead of clones but often a great reward. They have no great loyaly to Overshadow though despite the fact many have been trained by his fanatical agent in the Dreadmaster.