Once a family of the Dragon Clan, the Agasha abandoned their Togashi masters when they felt the Dragon abandoned their duties to the Empire. The Phoenix have proven much more amenable to their unique brand of magic. The Agasha are highly experimental and curious, always pushing the boundaries of what is known and what can be safely attempted when dealing with magic.
Of the eight Kami who competed within the first Celestial Tournament, seven went forth to honor their Emperor by creating Great Clans to serve him. Since that time, one additional Great Clan has been given leave ny the Emperor to serve him in the the same manner as the others, and one other self-titled "clan" has claimed the title but never been recognized.
In theory, the Great Clans command only what power is granted to them by he Emperor. This consists of the power to fulfill their specific duties without interfering with the duties of other clans, and to govern over the Emperor's lands bestowed to them in his name. In reality, of course, each clan commands considerable military, economic, and political power, enough to overthrow the Empire, and only the power of the other clans keeps them in check - that and the fact that no honorable Clan Champion would ever consider such a blasphemous and disgraceful act.
Although all Great Clans are ultimately loyal to the Emperor, they can and do have radically different outlooks on virtually every aspect of life, and conflicts between them are common. Most Emperors have historically chosen not to interfere with inter-clan wars because they permit the clans to vent their hostility honorably. After all, denying a massive force of noble warriors the right to pursue satisfaction in what they consider a matter of honor is generally a poor idea.
With regard to the subject of shugenja, the consensus of an entire Empire is that the Phoenix possess both the largest number of shugenja and most powerful of them. The descendants of the Tribe of Isawa and those who have sworn allegiance to them command mystical power unlike anything seen in the other Clans, and the followers of the Kami Shiba have sworn to protect them for all time, no matter the cost.
The Asako Family: +1Awareness [CR]
The quiet, reclusive Asako are a very monastic family, living scholarly and ascetic lives more befitting the Brotherhood of Shinsei than a family of samurai. They comprise the majority of the Phoenix Clan's courtiers, and the entirety of the mysterious Henshin monks. Asako are contemplative and inquisitive, but generally without ambition other than to serve and learn.
The Isawa Family: +1Willpower [CR]
The Isawa truly rule the Phoenix Clan, despite the presence of a Shiba Clan Champion. They are unquestionably the most knowledgeable, most powerful, and most numerous shugenja family in the Empire. Unfortunately, this has made them arrogant as well, and many Isawa constantly struggle against their own shortcomings.
The Kaito Family: +1Awareness [HR]
The Kaito were originally yobanjin of the Hyōketsu tribe assimilated into the Isawa family after the defection of Kaito no Momotsukihime, who would become the first Kaito Daimyō.
The Shiba Family: +1Perception [CR]
The Shiba are among the most scholarly and least aggressive of all bushi families. They serve the Clan and the Isawa without complaint or consideration for themselves. Although they prefer peace and compassion, the Shiba will not retreat from a battle once the Phoenix have committed themselves to an engagement.