The Noble Faction refers to the group of officials who are loyal to Ou Ki, a possible rival to Ryuuki for the throne. The group is largely comprised of officials from lesser noble families, who feel that the current king unjustly favors members of the Eight Clans. This section contains spoilers for later volumes of the Saiunkoku light novel series (starting from volume 12).
Many members of this group also harbour grudges against Senka , Ryuuki's father and the former emperor, for using the Wolves of the Wind to assassinate members of their clans found to be abusing their authority, thereby "purging" the government of corrupt administrators, while members of the Eight Clan went unpunished for similar abuses. The truth behind this persecution lies with the previous emperor Senka's desire to establish his rule. He actually belongs to the Shi family , strongest of the eight clans. In order to make himself the ruler, he killed every families that he considered is related to the Sou bloodline with no exception for women or children. Thus almost every noble families outside the colored clans were nearly purged with only a handful of survivors left.
Ou Ki (旺 季 Ou Ki) is the former Secretary of the Department of Royal Commandment Affairs . He became an imperial official through lineage instead of taking the official examanation. He is part of the four subsidiary families of the Shi clan.
Ki Kouki (陸 清雅 Ki Kōki) is the former Chief of the Censorate (御史台 Gyoshidai). Kouki is childhood friends with Anju. He entered the palace through lineage and is infamous as a cold and ruthless Chief.
Ryou Anju (凌 晏樹 Ryō Anju) is the former Deputy Secretary of the Department of Royal Commandment Affairs. He became an official through noble lineage but tends to remain neutral between the examination faction and the noble faction. In the novels, it is revealed that the former Emperor Senka exterminated Anju's adoptive noble family. Thus, it is not revealed where Anju really comes from. But it can be assumed that he might have been an illegitimate child born from Sa Sakujun's mother before her marriage into the Sa Clan.