There are plenty of characters that come and go throughout Jiraishin, but there are only a few main characters that are consistent through the whole series. I'm putting them here, and trying to be as spoiler-free as possible. ^_^ If you have any additional info or comments you'd like to add, please email me and let me know.

Iida Kyouya (Ky)
Kyouya is the best detective that Shinjuku Police Station's homicide division has to offer. ^v^ What else can I say about Kyouya that I haven't babbled elsewhere? *grin* He's very reserved; a real poker face type. He'll never show what he's thinking, what he's feeling.. he'll never let his emotions get the better of him. And he'll never let anyone close to him. He lives alone, in a tiny apartment. His job is the most important thing to him. Justice. That's what it is. But I think he feels a lot, and hurts a lot, underneath that cold mask of his. And don't ever get on his bad side. ^_^
Kyouya has no family, no lovers, no friends.. at least, none that he'll admit to. ^_~ His father was a cop before him, and a close friend of his boss, Narita. However, his father accidentally killed an innocent bystander while on duty, and couldn't live with the guilt; he commited suicide as a result.

Yamaki/Hachimaki (Mack)
Yamaki is Kyouya's partner, and the closest thing he has to a friend. Yamaki is also a real opposite to Kyouya. He's very talkative, friendly and outgoing, and his emotions show very readily on his face. So you always know what Yamaki really thinks of what's going on. ^_^ And he's determined to get past Kyouya's cold facade, I'm sure. He perserves, and I think Kyouya cares about him, too. He's not a tough cop that solves all the cases, but he's certainly a kind-hearted and generous one who'll make sure justice happens. (And for the record, Hachimaki is a nickname his workmates gave him; the kanji for his surname is usually read that way, and it also means headband. ^_^)
Yamaki has a wife, Yukari; at the beginning of Jiraishin they've been married for 3 years.

Narita (Nader)
Narita is the head of the homicide division at Shinjuku Police Station. He comes across very gruff and harsh, but despite that I think he really cares about all his men. Including Kyouya -- especially Kyouya. Kyouya is his best detective, and he knows it. His higher ups may want him to get rid of Kyouya, but he won't do so. (Extra brownie points for Narita! ^_^) Oh, he'll yell at Kyouya a lot and threaten him, but he'll still tell him to be careful when he's heading out to do something dangerous. It's just his nature to growl rather than to advise. *grin*
Narita's wife is dead, and he has one grown-up daughter, Atsuko, that we know of.

In my next life..
I'd rather be an emotionless flower..
However short a life span..