In the Marvel Civil War comics, there's no straightforward single winner. Both sides have their moments and losses, and it's more about the complex consequences and changes it brings to the Marvel universe.
Well, it's hard to say for sure. Different comics have different endings. Sometimes it's the underdogs who come out on top because of unexpected alliances or hidden powers. The winner often depends on the creator's vision and the themes they want to convey.
In the 'kronos wins the war fanfiction', it might be that Kronos discovers a powerful weapon or magic. This newfound power allows him to overpower his enemies one by one. He could also be very cunning in manipulating the internal conflicts of his opponents, which in the end helps him win the war.
In 'loki wins the war fanfiction', a frequent theme is Loki's self - discovery. As he battles through the war, he learns more about his own capabilities and his place in the universe. Also, the theme of subverting expectations is common. Everyone expects Loki to lose or cause chaos in a negative way, but in these fics, he uses chaos to his advantage and wins. Another theme could be his complex relationships with other characters being reforged through his victory.
If Robb won the war in a fanfic, it could lead to a completely different Westeros. He might establish a more just rule in the North and perhaps even expand his influence over other kingdoms. Maybe he'd form new alliances and bring about an era of peace and prosperity, unlike the chaos that followed in the original series.
In some fanfictions, Naruto wins the war through a prophecy. It was foretold that he would be the one to end the war, and so he is given special powers or artifacts that help him achieve victory. These powers could be something like the ability to control time briefly during battles or to summon ancient and extremely powerful creatures that tip the scales in his favor.
Maybe Voldemort manages to defeat all the major resistance. He could start by taking out key members of the Order of Phoenix one by one. For example, he might ambush Sirius Black early on, weakening the Order's intelligence network. Then, he'd target Dumbledore, perhaps using some dark magic that even Dumbledore couldn't counter. With the two biggest threats out of the way, he'd be able to overrun the wizarding world, starting with Hogwarts. He'd install his own regime, making pure - blood supremacy the law and punishing those who oppose him severely.