Noragami's central idea is that gods are only as powerful as their worship, and Yato has almost none. He's a delivery god working odd jobs for five yen a time, sleeping rough, and desperately hoping someone builds him a shrine.
The shinki system is what makes the series more than a supernatural action show. A god's weapon is the spirit of a dead person, bound by a name the god gives them, and that relationship is a genuine responsibility - if the shinki's heart is poisoned, the god feels it as physical corruption. Betrayal is literally a wound.
Yukine's arc is built entirely on this. He's a bitter teenager who died young and resents everything, and the process of him becoming something other than that is painful for everyone involved.
Hiyori is the human anchor, stuck half out of her body and refusing to leave either world, which is a good metaphor for the whole show's tone.
This collection covers Yato, Yukine, Hiyori, Kofuku and Bishamonten. Five yen and a wish, effectively.