Still heavily under construction, but here is the Character Relations chart for Ciel. I've tried to get anyone he's had significant interaction with. If I've forgotten anyone please comment and I'll be glad to add you.
Enemy
Unfriendly Acquaintance
Acquaintance
Friendly Acquaintance
Friend
Close Friend
Romantic Interest*
Servants
usedcalmmind Sebastian Michaelis
"Yes, my Lord."
Sebastian is Ciel's butler, and most reliable servant. He can never lie to him(or so he thinks), and will(supposedly) follow any order Ciel gives him. They often like to play mind and word games with each other, and Ciel will go out of his way to point out minor mishaps to Sebastian, or put him in situations that Sebastian might find displeasing.
one redcinematics Grell Sutcliff
"I have no desire to be near you anyway. Not when you're alone, at least."
Grell is an annoyance that needs to be dealt with. Unfortunately he's also helped Ciel out on occasion, when their priorities cross. However Ciel will never like him, one for his overbearing personality and constant attention to his butler, but mostly because Grell killed his aunt. And one day Sebastian will finish him off.
one no1canbreakyou Shadow the Hedgehog
"Bringing happiness. I wonder what the purpose of that is.?"
Ciel's only had one conversation with Shadow, but they seem to have some things in common perhaps?
one trollsikebukuro Izaya Orihara
"Disappointing, isn't it? You're just as unknown as everyone else when you arrive here... "
Ciel spoke very briefly to him over the network.
one gochuugoku Wang Yao
"Phantomhive? That sounds like an English name."
Ciel has spoken to Wang Yao a couple of times, and doesn't seem to mind him much. He seems reasonable, which is more than he can say for some other Chinese man.
one ♠
two clockworkaholic Julius Monrey
"... I take it you know each other."
Ciel's just met Julius, but he's polite and quiet enough. And having briefly traveled together he's leaning toward 'friendly acquaintance'
one ♠
two freshbreeze Ventus
"...whenever we manage to go back, it'll be like we never left."
He's only spoken to Ventus once, but Ventus said something that piqued his interest about returning home.
one complexrestart Rika Fururde
"... My friends were there for me when I became orphaned."
Ciel's spoken to Rika a couple of times over the network. He doesn't find her annoying.
one pineapplet Chrome Dokuro
"But it gets better, I suppose."
Ciel's spoken to Chrome oncetimes. He doesn't mind her. However he will mind her relationship with Sebastian.
one oldestfriend Dee
"Funnily enough, for you Ciel, I'm worried more about the practical than the unusual. "
Having spoken to Dee a few times now, Ciel is not quite sure what to make of her. She acts friendly toward him, but she knows things she shouldn't know and that unnerves Ciel. He's suspicious of her, and is pretty sure she's not human. At the same time, she is rather friendly, and buying him cake these days which earns her points.
one ♠
two miniworth Miles Edgeworth
"I'm the son of a lawyer, I want to serve her justice..."
Ciel quite likes Miles. They've spoken a few times over the network, and he finds him to be a bit of a breath of fresh air. Plus a boy his own age. Though Ciel cares little about 'justice' in the sense of the law, it's good that some people do. Ciel looks forward to possibly meeting him someday.
one ♠
two ♠
three ♠
four *For a given value of 'romantic.'