This fourth omnibus, comprising volumes 10-12 of the 20-volumes in The Last Order, clocks in at over 600 pages. Yukito Kishiro was clearly milking the series while trying to figure out what to do and I get the impression that he's very much a seat-of-the-pants writer. Hence, in the last omnibus we got hundreds of pages with no Alita, just a post-apocalyptic story about vampires.
In volumes 10-12, fortunately, Alita is back. (And the vampires have basically disappeared from the story.) It's been a couple thousand pages now, but you might remember that Alita originally went into space to find the brain of her friend Lou, who used to be her "operator" when she worked for Tiphares. Well, Alita's quest to save Lou gets mentioned maybe once or twice, but first, we have more pages and pages of freaky transhumanist mortal kombat teams fighting in the ZOTT. You know, that outer space tournament that's been going on for the last half dozen volumes.
With Alita back in the fight, it gets more interesting again. Alita has been resurrected (again) in a brand new even more super-powerful cyborg body (again) and for some reason, she is now a catgirl with a cybernetic tail. Wtf, Kishiro?
Aga Mbadi, aka Trinidad, who's the Big Bad of this series (so far) finally gets taken down a peg, and we learn his origin (it's still a little incoherent). Dr. Nova now has multiple clones, and they aren't all on the same side. Alita's rival (who's kinda on her side for the moment) is a hypermacho super-powerful cyborg space karate fighter named Zekka.
There is a lot of action. A lot of Alita kicking ass. But the series continues to be mostly an ever-escalating series of boss fights, with the writer occasionally remembering to mention the plot. There is a little bit of story advancement here, but at this rate Alita will have to fight the entire solar system before we get to the climax.