Family
This section covers the Ryudo Family and relationships with them.
Nakahara
Nakahara is the boss of the Ryudo Family. He is very fatherly towards his men and adopted daughter Saki. His tattoo is of s Shiisaa (Lion Dog), if I'm not mistaken. I'm not really sure how Nakahara and Rikiya met but they are close. Rikiya would do anything to make his boss happy. The Ryudo Family is more liked in Ryukyu then the other Yakuza family that is there. Nakahara holds a lot of the deeds around the area, including that of Sunshine Orphanage. Nakahara becomes sworns brothers with Kazuma after he saves his daughter Saki.
Mikio
Mikio is generally seen with Rikiya or the Sunshine kids (mostly Izumi). He is a good kid and when on patrol store owners give him food. He is more than willing to protect them and they would do the same for him. Ryukyu is very close nit unlike Kamurocho. The Ryudo Family does a very good job in taking care of it's people. Mikio ends up watching the kids while Kazuma and Rikiya go to Kamurocho. He is very much like a big brother. Izumi even cons him into making a dog house for Rex which Mikio later defends from some Yakuza. Rikiya and Mikio aren't only comrades but they are like brothers.
Saki
There isn't much interaction between Saki and Rikiya. I'm sure they care for each other, it's just not shown a lot. Rikiya does run after her if she is kidnapped or runs off. She's very important to the Ryudo Family and later makes friends with the Sunshine kids. Saki doesn't talk much, so it's hard to understand her. She's a very good artist too.
Kiryu Kazuma
Not really in the Ryudo Family but he is a sworn brother to Nakahara and Rikiya idolizes him. Kazuma teaches Rikiya a lot about being Yakuza and being a good man. After Rikiya gets his tattoo finish, he claims that he and Kazuma are like brothers because they share the same ink. Rikiya constantly calls him "Aniki" which is big brother or honorable big brother after Kazuma defeats him. Seriously Rikiya follows him around like a puppy. However, they are close though, even though they didn't know each other for a ton of years they are just as close as people who have. They mean a lot to each other and have each others backs. They also fight about the other not having any fashion sense.