Fuyuki Hinata

Similar to the FUNimation version, he's generally a lonely and unpopular geek (though rather than being interested in the paranormal, he's mostly interested in attracting women) who doesn't have any friends whatsoever. Earlier on, he also has his usual obsession and/or fascination over Keroro, though this aspect of his personality eventually fades away (probably figuring out how much of a jerk Keroro actually is) as the two both become mostly indifferent to one another, rather than being best friends, like in the original versions.

History of Characterization
Fuyuki had little-to-no changes throughout the series, though when MontHenryKnitly started writing for him he's a bit more scatter-brained than he was before (though to be fair, he's still probably one of the most sane characters).

Relationships
Keroro - At first, Fuyuki seemed to admire Keroro a great deal. But after awhile, both of them seemed to share apathy towards one another. They seem to be on fairly good terms, though, as they hang out with one another and chat, on occasion.

Kululu - Despite having never really met (at least for very long), Kululu has an extra lust for Fuyuki, compared to other characters. Despite this, Fuyuki himself is completely oblivious to Kululu's attraction and may not even acknowledge his existence, if he's even aware of it.

Natsumi - Being brother and sister, they have the typical sibling rivalry... though it conists of Natsumi demeaning Fuyuki in whatever way she can. When she isn't doing this, though, their relationship is much more friendly.

Aki - Seeing as she spends most of her time at work, they don't spend much time with each other. When they are together, though, Aki seems to be somewhat passive agressive to him, despite being his mother.

Momoka - She's probably the only one who actually likes Fuyuki... but maybe a bit TOO much. As such, she obsesses over him 24/7. Though unlike the show, where Fuyuki is [seemingly] oblivious to all of this, Fuyuki is now completely aware and just views her as a creepy stalker.