Fukuda is a very sociable person. He loves to stay together with people that he likes and he always speak of anything, saying grossly his sincere opinion without using kind words. He's direct and many people hate this side of him, so even if he became friend of Saiko and the others, he doesn't seem to have other friends. Or, simply, they're the best friends he've always known. :)
Fukuda is always
minded to
help the others, even risking his carrier, because if someone has reason, he always want to support it.
FUKUDA & SAIKO
Fukuda and the main character of the series.
Their relation borns when Saiko becomes an assistant of Eiji, because in that moment, Fukuda was his assistant too. In a first time they share some wrnagle, because Fukuda's personality is the totally opposite than the Saiko's one. But in a second moment the find a way to be friends.
Fukuda always support Saiko saying his sincere opinion, and Saiko loves this side of him (than he calls Fukuda "Fukuda-san". Fukuda admires Saiko's determination and he considers him a rival. Their relation is a sort of friendship/rivalry that always involves them with trust and recicprocal respect.
Fukuda proves his friendship
in the moment in which Saiko risked to be deleted from Jump because of his sickness. Fukuda organized a boicottage in order to help him, because he knew that the boss editor was dropping Detective Trap just because he was afraid that Saiko 
would embrace the same destiny of death of his uncle, Kawaguchi Tarou, that died for his manga. Fukuda, Eiji, Aoki, Nakai and Hiramaru stopped their manga for a week, and they menaced the editors to stopped them forever.
Saiko was very happy for Fukuda's act, but I can't enabled them to risk their carrier for a mistake of him, so he aked to Fukuda to stipping the boicottage. He always would drew but his friends have to continue their story, and not just for them but for the lectors, that follow them with impatience.
The boss editor has decided to stop Saiko and Shujin until their graduation, but Saiko drew 12 chapters of Detective Trap even in hospital and since the manga is pubblished for a time in a week, Saiko can drew a chapter every 2 weeks.
The boss accepted their propose
and riammitted Detective Trap in Jump, so Fukuda was satisfacted. XD
Fukuda knows very well that his draw aren't good like the ones of Saiko, but even if he admires (and is a bit jelous) him, he feels like his direct rival. But that reason doens't stop him to consider Saiko a friend, and Fukuda always stay with his personal cellphone, calling him everytime he has something to say. XD
He always calls Saiko making his best compliments
(with cursed and abuses,
calling somebody every name under the sun) and remembering him that one day I'll beat him and Detective Trap. Saiko considers him a strange person but definitely he likes him and he follows many of his concils in order to make better his manga and himself as mangaka and person.
FUKUDA & SHUJIN
They haven't a real relation. Fukuda adore Shujin's ideas and he always thought about him as a genie. But when he read the name "Ashirogi Muto", he thought about just of a single person, not two. So it was a surprise for him to find that Ashirogi Muto was a pen name that encloses two persons.
He admires Shujin's mind and he considers his ideas as truly
brainwaves. In their fist meeting, Fukuda kindly bows his head in order to greet Shujin, saying that Saiko and him together are his rivals... It can't seem but he's a bred boy! XD
FUKUDA & EIJI
Fukuda started his carrier working as his assistant. In past he presented two times a manga and he always received a special mension, but no pubblication. So working together with Eiji, he thinks to makes better his tecnique, finding the secrets of a genie. Working together with Eiji, Fukuda was starting to think that he was a totally idiot, because he never made a meeting with his editor in order to decide Crow's development, and he never done a name. But Fukuda is a nice boy u_u and he learned to Eiji to do a name and to become more responsable as mangaka. 
Also, Fukuda says to him all the changement that in his personal opinion could make better Crow, and Eiji modified it.
Eiji's ammiration for him is very
high, so he calls Fukuda "Fukuda-sensei". And he always follow Fukuda's words. Eiji is the first person that joined the boicottage and until the end, followed Fukuda in his plan. In the chapter 51 Fukuda calls him in order to do something for Detective Trap and
Hideout Door, that was risking the dropment. But this time Eiji says that he can't do nothing, because are them that must do something for theirself, so
Fukuda understands that Eiji reasons with his proper mind
and if he want to make something, he needs to make it alone.
FUKUDA & YUUJIRO
Yuujiro is Fukuda and Eiji's editor. But he makes correctly his job just with Fukuda, because things as to do meeting in order to siscuting the name of the manga should be clear for a mangaka, but Yuujiro is lazy and he never say nothing to Eiji. So Eiji didn't know nothing about meeting and what's a name, Fukuda learned all to him.
Also, Yuujiro thinks that follow
two mangaka is stressing, so I hopes that Fukuda's manga will be
dropped. He really think that Fukuda is a good mangaka (even if he considers him a problemtaic element), but he's too lazy to work well for two of them. Fukuda
doesn't put his trust in him, he understood that Yuujiro doesn't do his best.
And everytime some Fukuda's work is pending approval for Jump, he calls Yuujiro 100 times in an hour, thinking that Yuujiro is not affidable. Also, Fukuda always say his opinion in order to makes better Jump but Yuujiro doesn't care about him and his thoughts.
When Fukuda organized the boicottage, he made Yuujiro crazy, because Yuujiro knew that there's no way to change Fukuda's ideas and decisions. Saiko's words are the only thing that stopped him.
FUKUDA & NAKAI
Nakai works in manga's world since ten years ago, and in that arc of time he never got a serialization.
Fukuda
makes fun
him saying that he's a good assistant and stop, and Nakai hates him, but there's a different, because Fukuda always say his thoughts to him, Nakai keep his cursed and consideration about him in himself, and he's silent in front of Fukuda, but when Fukuda isn't present, he
speaks ill of him, like the moment in which Nakai remained alone with Saiko and he cried for all the night because of Fukuda's words, cursed him.
Fukuda is a clear person, and even always saying his opinion, he respects Nakai a lot, Nakai doesn't respect him.
When Aoki decided to stop Hideout Door in order to do a manga with Koogy, and Fukuda knew that Nakai spent all his time drawing
covered by snow in front of Aoki's hause, he follow him in order to know if he really stays well.
That time was winter
and Fukuda spent there with his moto and dressed with a great coat, and just for him.
He called Saiko explained him the situation, but he didn't lift a finger because he respected Nakai's decision as the one of a true man.
Saiko says to him that life is more important that pride and Fukuda understands that the better thing to do is to save Nakai, that
frozen solid from snow and ice.
Now Nakai understood his mistakes and he got a series. So he know very well that part of the deserve is of Fukuda and Saiko, so it seems that he changed his idea of him.
FUKUDA & AOKI
After 51 chapters, I happily can say that Fukuda likes just manga-girls, nobody else.
He doesn't like Aoki and he thinks that her style is too girlish for
a shounen. Aoki doesn't like him considering Fukuda just a rough boy without brain. In her personal opinion Fukuda's Kiyoshi Knight is horrible.
But she joined the boicottage, and that meanings that she hasn't that bad opinion of his ideas. She can agree even if an idea comes from Fukuda.
FUKUDA AND YASUOKA
Yasuoka is the only assistant of Fukuda and he always "sells" his (and his friend) ideas to Fukuda, that initially pays it 1000 yen, and after a good position for Kiyoshi Knight, 3000 yen for other good their ideas like that one. Yasuoka thinks to works too much and he desires another assistant, but Fukuda says that a person is quite sufficient for his "draws of shit". XD
FUKUDA & HIRAMARU
Hiramaru just follows Fukuda in each his strange idea because he really desires that his serie will be dropped. So Hiramaru always agree Fukuda's ideas, joining the boicottage like the others, and it's because he knows very well that if his series jump a week, he can relaxess for 7 days. And if his series will be dropped, he'll be happy too, he's tired to work like a mangaka. XD
