The story isn't all over the place as much as it is fragmented. Granted it's a war arc but in all honesty it follows your usual isekai formula. Main group faces enemy, main group gets stomped on, protagonist does some risky training/technique to get a power up, main group manages to survive another day. I'm not saying it's a bad plot, I'm just saying it's nothing ground breaking. Also they add even more new characters that unlike the original cast, the new characters are mostly forgettable.
What this season does really well is again world building and using the anime's foundation to help set up in my opinion some pretty cool plot points. That and it really drives in the narrative of both sides are guilty, where in the beginning it wrote the vampires as evil it quickly shows that the humans aren't much better. Though also like the first season the vampire's motives still aren't very clear other than "we need to stay in control".
The fight scenes are decently choreographed and there's a lot more of them than season 1. The art style holds up well as usual, especially in the designs of the demon weapons and their powers. So if you liked this anime for the mindless bloodshed, you're in for a treat. But unfortunately with no clear ending in sight and no update, at the time of typing this, 6 years later, who knows when or if we'll get another season. All and all Seraph has me again wanting me to sink my teeth into more.
Thank you for reading my review, enjoy the rest of your day/evening.
