Is Shiki and Rima in a relationship?

Shiki and Rima are both models who met while on the job and later became inseparable. They work together on many occasions and they take on assignments from the Vampire Council to hunt down Level E vampires. The two of them share similar personalities and are almost always seen together. They are shown caring about each other's well-being often, showing their relationship of very close friends.

～nawaki