Others
The characters on this page are important to Reiko's story, but didn't have as much interaction as the other characters I wrote about. Even though there isn't as much to write about them, I still wanted to cover them.
Goto & Miki - Goto and Miki were the result of parasite experiments conducted by Reiko. They were in a sense the perfect parasites, seemingly unbeatable, but Reiko viewed them as weak. Miki and Goto both have a huge amount of respect for Reiko. Miki is grateful to her for his life, and he helped Hirokawa and the other parasites see just how much Reiko has done for their species, saying they wouldn't be as advanced without her. Goto was a lot quieter than Migi, but his respect is evident as well. He told Reiko it was good to see her, and he treats and looks at her with the respect of an elder.
Hideo - Hideo and Reiko had a lot of interaction compared to the others on this page, but they didn't have much of a relationship. The dialogue between them was mostly to exchange information. Reiko asked Hideo to observe Shinichi for her studies since his host body was about the same age. They obviously spent some time together as Hideo preaches Reiko's views on parasite-human coexistence to Shinichi, but he doesn't act on those views, so it's obvious he doesn't share them. Hideo asked Reiko how Hirokawa was, so they probably met through Hirokawa's cabal.
Hirokawa - Hirokawa led a parasite cabal that was highly influenced by Reiko's ideas for human-parasite coexistence. He was elected mayor in a small city near Shinichi, and he used his position to set up “dining rooms” or “safe houses” for the parasites to feed in private. It's later revealed that he was human, and legitimately concerned about the environment. He was a parasite sympathizer. He and Reiko don't talk much in the series, but from the few times they do, it's easy to tell that Hirokawa really respected Reiko. He often took her side over Kusano's.
Hirama - Hirama was the lieutenant who ordered his cops to shoot Reiko. There wasn't much interaction between the two of them, as he wasn't interested in coexisting or learning more about parasites. In his eyes, parasites needed to die, and because he had only gotten information about Reiko from Kuramori, Reiko was THE parasite to kill. It's sad, because before her death, Reiko was giving Shinichi information on the parasites. I bet if he would have taken the time to cooperate, Reiko would have been an interesting asset in his investigation against the parasites.