In the light novel, they have an antagonistic relationship that is shown between them, with each one of them having his own way of ruling over the school. Manabu is shown to have some worries about the future of the school case Miyabi continues reigning over the school as the 'Student Council President', going as far as to establish an Anti-Nagumo movement.
Honami seems to hold Miyabi in great esteem, thinking that the two of them are quite similar since he started in Class-B and climbed to Class-A, it is also by dint of his involvement that Honami got finally accepted in the student council. That aside, the relation between the two of them, as for now, is quite good. However, Miyabi is hinted at being a womanizer and when Ichinose needs private points to save her class, he agrees to lend her the points on the condition that she 'Go out' with him. Ichinose is very reluctant to accept this offer and ultimately declines.
After seeing Kiyotaka's performance in the relay race against Manabu, Miyabi became somewhat aware of Kiyotaka, but still not thinking of him as a legitimate threat. He's also aware of the fact that Manabu regards Kiyotaka very highly, commenting to Masayoshi Hashimoto that he's regarded higher than even Sakayanagi or Ichinose among the 1st year students. His interest in Kiyotaka only grows as is seen when he asks Sakayanagi if she knows anything about Kiyotaka.