The Seishi of Fushigi Yuugi are actually based on ancient Chinese starlore, which divides the sky into four sections based on direction. Each is governed by an animal deity. The "Four Gods" refers to the guardians of East, West, North and South. These gods are each given seven of the twenty-eight constellations in the sky. The world is divided into 4 sections as well, with each of the four countries being under one of the gods' rule.

	
Genbu	Suzaku	
The Tortoise	The Phoenix	
Hokkan - Northern Country	Konan - Southern Country	
		
Seiryuu	Byakko	
The Dragon	The Tiger	
Kutou - Eastern Country	Sairo - Western Country	
Whenever one of the countries is in danger of being extinct, the prophecy states that a girl from another world will come and gain the divine powers of that god, becoming his Miko, or Priestess. Each Miko has seven Seishi, or star warriors, who protect her and help her to call her god. Each Seishi represents one of the seven constellations in the god's sector. Every Seishi is marked by a character on a part of his/her body. The character is the name of the main star of their constellation. 

"Four Palaces of the sky and Four Divisions of the earth, possesses great power, believe and goodness. Reporting to Guardian of the South, Suzaku Your Majesty, please listen to my announcement. The reason for Shichi Seishi to come down to earth is to save the people who respect you. Right here, destroy all evil, use your divine power to save and protect us. Hope you will listen to my prayer. Please decend from the sky to our side."
- Miaka's spell to summon Suzaku