The following contains spoilers for X-Men #13, on sale now.
An interesting thing that has popped up a few times so far in Jed MacKay's X-Men run is seeing some fascinating homages to past classic X-Men stories. For instance, in X-Men #5, MacKay did his own version of the classic New X-Men issue where Jean Grey and Emma Frost go into Professor Xavier's mind, and now, in the middle of the X-Manhunt crossover, MacKay is doing a clever spin on the Dark Phoenix Saga through the use of Eternity Storm, which is the general term people have been using to describe Storm, who is currently sort of merged with Eternity (or the host of Eternity? It's all kind of a semantics deal), who tore through Cyclops' X-Men team in the last chapter of this crossover, as Storm has decided to help her old mentor and friend, Professor X, who is on the run after escaping from Graymalkin Prison, but what Storm doesn't know (because her power is so great that she is essentially immune to Xavier's powers) is that Xavier has been infected with a mutant tumor that is causing his powers to go haywire (and causing Xavier himself to lose track of his own sanity), and so he really needs to be taken down before he does too much damage (of course, though, Xavier is driven by a desire to save his daughter, who is dealing with a coup in outer space as part of her role as the Empress of the Shi'ar Empire).

X-Men #13 is from writer Jed MacKay, penciler Netho Diaz, inkerw Sean Parsons, colorist Fer Sifuentes-Sujo, and letterer Clayton Cowles, and it is a striking spotlight for two major fights, one between Xavier and Kid Omega, and one between Storm and the rest of the X-Men (who have regrouped after Storm kicked their ass at the end of the previous chapter of this crossover).

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How does Netho Diaz differentiate between the fights in the issue?
Something that has been very compelling in Netho Diaz's time on this series is how attuned he is to the ways that an artist can differentiate between different stories within the same comic book. What I mean by that is that MacKay has frequently been telling two very different stories in each issue, like, for instance, in issue #10, he had Cyclops having a talk with a government agency in half of the issue, and the Hellions destroying Sentinel factories in the other half of the issue. In that issue, Diaz used one style for the discussion, and another for the Hellions.
Similarly, this issue is split into Kid Omega's duel with Professor X, and Storm's fight with the X-Men. In the Xavier/Kid Omega part of the issue, Diaz does a different style, and the colors by Sifuentes-Sujo are just outstanding. It really stands out, and makes you feel like you're in another world, which works perfectly for a battle that is taking place within the minds of two omega telepaths.
I liked the idea of how Xavier and Kid Omega's battle ended, where MacKay got the result he wanted without actually stating that Kid Omega truly "beat" Xavier in the traditional sense. That's the best way to do these sorts of things, so that you can always say, "Hey, who knows what the NEXT time will be?" The way Kid Omega won was a sharp callback to a previous issue of the series, and it was nice to see MacKay tying things together nicely like that (I wonder, though, if perhaps an editorial box, something like, "Remember from issue #5?" would have been nice to include there).

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How was Eternity Storm's battle with the X-Men like the Dark Phoenix Saga?

So Diaz used one style (and Sifuentes-Sujo used a distinctive coloring approach) for the battle in Xavier and Kid Omega's minds, and he used a different style for the X-Men's battle with Eternity Storm. Just NATURALLY, from him working on this book for so long now, we've seen a steady evolution of Diaz as an artist, and while he has always been really good at action sequences, he clearly kicks things up a notch in this issue. The Storm/Juggernaut fight is some of the most electric (no pun intended) fighting sequence that you'll see in a X-Men comic book. It's amazing to compare this with just Diaz's work on the Heir to Apocalypse miniseries of just LAST YEAR! The sharpness of the pencils is so much better now. He's kept all of the dynamic nature of his earlier work, only the character work is so much sharper. It's just outstanding work. Marvel clearly has a star artist here in Diaz.
MacKay, meanwhile, turns to the Dark Phoenix Saga by having the X-Men try to talk to Ororo within Eternity Storm, and have her take control of the situation. It's a great sequence, where Psylocke threatens to kill an innocent unless Storm stops the fight. It is a lot like when Jean Grey took control of the Phoenix Force in the Dark Pheonix Saga. It also reminds me a BIT of John Byrne's classic Man of Steel issue where Batman threatens an innocent to control Superman (of course, unlike Batman, who was only threatening his OWN life, Psylocke really WOULD have killed an innocent person if she had to). It's a great character moment for Kwannon, who is obviously in a weird spot, characterization-wise, when her predecessor as Psylocke is so much more famous and well-known than she is.
This crossover has been a bit all over the place so far, but this issue was a real high point.
Source: Marvel