Blood Monarch, a Demon
The captains and the soldiers worked together to set up the camping site as quickly as possible — Arthur also helped, although in his time, working less than the others.
His primary goal of making them attack him worked, so there was no reason for him to keep acting like a lazy leader who would not do a thing for his soldiers. That would make them see him badly, which was the opposite of what he looked for.
Vampires did not burn with the sun, but that did not mean they didn't need to sleep, and the perfect time for it was during the day — when their powers diminished, unlike night when vampires were stronger.
Even though Arthur was stronger than them and had special abilities from the Blood Monarch's inheritance, he still followed the same rules, and at that point, he also needed to sleep, like everyone else.
They built up large tents and placed many sleeping bags inside where the soldiers would sleep. As for the captains, they would sleep inside their carriages alone.