If Kouta actually died from disease that would make for a truly ignominious ending. A complete waste of every good thing pre-kidnapping arc that has happened before. But we just know it's impossible for the protagonist to die unless resurrection/reincarnation are established concepts in a story, which are not here.
Man, this is so annoying. This encounter could've been prevented had a battle between Clara and Juliana happened last chapter which Clara would've easily won. If I'll be optimistic, Clara and Akito will arrive just in time to help, so it still becomes Clara vs Juliana, but with extra steps. If I'll be pessimistic, Juliana and her thugs will quickly beat Emma and successfully kidnap Kouta again, so we're back to square one and the damn kidnapping arc won't be ending soon.
I don't think their beastkin friends will be back soon, but even if they did they were porters, not fighters so it won't help the dire situation much.