- "Ah, few things in nature are as misunderstood as the playful salmonella bacterium. S-Typhi is the little dickins that--"
- — Hiro, mocking Kamal's cooking
Hiroyuki is Kamal Zaman's roommate at a medical school in the region America of Earth. He is the more humorous of the couple, and he often makes vague innuendos that make others suggest he finds a girlfriend. However, like Kamal, he is rather geeky and needs to read "How to" books to try to understand dating.