This world is divided into sentinels and guides, I'm not sure if there's ordinary people but those are the two divisions. At a certain age, you differentiate into either one. The spiritual power of both the guide and sentinel usually manifests in the form of spirit animals. They are both divided further into S,A,B,C,D,E and F classes with S being the ones with the strongest spiritual power and F being the lowest. For sentinels, they are like espers, they fight and their spirit animals also help with that. For guides, they are like healers who help sentinels who have over used their power. The classes usually don't change after differentiation unless you have a second awakening where your spiritual power increases. In this kind of society, people Revere those who are strong because you get access to more resources and better treatment when looking for jobs. Anyways, this is in general how the Chinese guideverse usually is.

I'm at chapter 8 and I still don't know what each class means, what they do, what are their significance and how does it affect them from day to day life to finding a job since ot was emphasized at the elevator scene.
I don't wanna continue the story anymore because of this and the sa at the start:(
Have fun for those who's gonna stick around(๑•ㅂ•)و✧