According to sources and the wiki-- Delphine killed her and Dio's father, Darius - something we know! Said sources and the wiki only mentioned Darius. The Chronicle books says that Delphine killed "their parents," which confirms the mother as well. And not only that, but a young Dio kind of saw it happen.
Obviously, after an ordeal like that, Dio was all kinds of emotionally fucked up -- and lonely. So Delphine decided to get him a servant, thinking that he was just lonely for his parents (but mainly really because he thought she was going to kill him too; she didn't know that he saw what she did). Lucciola was chosen specifically by Delphine for Dio, because he was Cicada's younger brother and thus had a strict upbringing. And Cicada to Delphine had shown a devout loyalty and possessed mad fighting skills and such. Lucciola was also chosen at an age one year lower than servants are usually chosen at-- probably because of the special case of Delphine needing someone to satiate Dio's loneliness as well as keep him safe from potential rebels as a result of the purge she made on the other Guild houses.
Dio gave Lucciola his name. Naming is apparently an Important Thing and a high honor for the servant class. I believe it mentions something about how "lower" people in the Guild don't really have names outside of what their jobs are? And a difference between being a "part" of the Guild and "a person" of the Guild with a name. And once named, they are required to pledge their absolute loyalty to whom they serve. And since Dio was more or less compliant to the Guild laws, Lucciola had no problems staying completely loyal to Dio because he wouldn't be going against anything Delphine didn't want Dio to do.
Of course, Delphine was possessive and cruel, so became jealous because Dio was instantly attached to Lucciola because he had been sad and lonely since his parents were killed and he liked him more than her. So she began to suspect Lucciola and wonder about his loyalty to her-- the Maestro. She didn't want to do anything to him like kill him because that would only make Dio worse, so she went about it in other ways. She'd make sure to take Lucciola aside to talk to interrogate him to ensure that he wasn't "straying". And did things to remind him of the power she had over them all -- one thing mentioned specifically was her not letting him eat as punishment (oh, hello series flashback scenes).
It goes on to say that the food plan ended up backfiring worse for Delphine, because the bond between Dio and Lucciola grew as a result of Dio doing things like sneaking him food.
In Lucciola's case, he made sure to be even more careful, keeping his personality, attitude and posture perfect to keep Delphine assured, since if he showed anything kind or familiar to Dio and she found out, she would kill him.
And in Dio's case, he was always interested in Lucciola's feelings, wanting to see how he really felt behind the very rigid posture he kept for himself. So he would always do crazy things to get reactions out of Lucciola, to see him look bothered, or sometimes angry, and sometimes maybe to even smile. For Dio doing things like that was easy because Dio was always the kind of selfish person to want to troll around and make things complicated.
Dio never had any interest in the politics of the Guild or anything like that, and preferred to just go and do whatever he felt like - ala how he did his own thing after the Horizon Cave race and went to the Silvana. When he disappeared, Delphine didn't really pay much mind, because she could always contact Lucciola wherever he was via his earring device to order him. (I'm not sure if it's contact him or track him -- it could be the latter, considering the things that came up in the latest Travelers chapter).
When Delphine did board the Silvana, non-compliance or attempted counters to her could have resulted in massacring the entire crew, so Lucciola followed her orders. Due to the strength Delphine took with her, they had no choice but to go-- which was why Lucciola was doing things like stopping Claus from doing anything stupid (when they went to Guild as well). Because Claus was important for Lucciola's plan to possibly free Dio after he was brainwashed. Lucciola also didn't expect Dio's brainwashing to be as deep as it was-- apparently Dio's was different from the norm and his personality had been completely reprogrammed.
When they were taken back to the Guild, and Lucciola made his decision-- he chose Dio over his dedication to Delphine because his friendship with Dio was more important to him. Giving up his life in order to protect those bonds was something that he was okay with. Delphine of course, was deceived-- she had taken Claus to the Guild because he appeared to be "the first friend Dio's ever had" which was why she asked Lucciola what he was to Dio in the end.
Oh god the way they worded this part-- okay, so when Lucciola responds with "I am Lord Dio's friend" he says it with pride. He could have lied and responded saying he was a servant to save his own life. Because he didn't want to betray his relationship with Dio, he responded how he did, and it clearly shows that Lucciola was a person, an individual who made the choice he did himself.[/quote]
Here's points of interest from Cicada's profile:
- When they mention Cicada and Lucciola being brothers, the term/phrase of "same genetic source" comes up. And they do mention genetic manipulation in general in the next paragraph.
- It talks about two ways to become a "Guild member." One is, obviously, being born into it. The other talks about educational and military institutions, where only the best are chosen from, but still just for lower class/servants. They came from "the ground" are are known as "apprentices" as they learn/train. And when the best of the best are chosen ... they get a test at 17, which, if failed, resulted in a mind-wipe which is what those Guilders with the weird makeup and chanting all are.
- Guild uniforms and ranks.
Maestro: Wears whatever they please.
Chief Agent (called Lorica, aka what Cicada is): Wears black
Next Maestro (also, what Dio SHOULD have been wearing): Wears black
Subordinates to Delphine (called Scutum, aka Delphine's other servants): Wear grey
Subordinates to Dio, also Delphine's maids (called Aspis): Wear grey
Everything else below that: Wear white.
HOWEVER. Dio, because he is the master troll, decided he liked wearing the white servant uniforms. And so not to dress as though they outrank him, Dio's servants all wore white as well, with silver collars. Dio's collar is gold to separate their ranks. Awesome job, Dio.
And finally, a couple of the What's Dio Thinking summaries:
"He's not good, but there's some sort of glimmer about him."
The way Claus was flying seemed to be reckless, not bound by any sort of rules. It also mentions Dio's birthday approaching -- and I think it says something along the lines of that he was looking for something to DO with himself to keep himself occupied, so Claus stood out.
"If I say your name is Immelmann, your name is Immelmann."
Something about how there are names in the Guild for people who are around on a regular basis (maybe referring to the earlier talk about how naming is important?). And how this was a fresh experience outside of the Guild-- maybe in that since it's not a Guild-regulated kind of naming/nicknaming it felt nicer to do?
"Lucciola get out, now!"
After being ignored by Claus, Dio was pissed off because nobody ever ignored him before, so reactionarily snaps because he's losing on top of that.
"It feels like I can touch the clouds!"
Dio has no sense of crisis-- there was an emergency happening and he ignored it to go up on deck. It also says that it might have felt like a feeling of freedom to Dio at the time.
"If it tastes good, you should let it show on your face, Lucciola!"
Dio's time spent on the Silvana meeting everyone helped him express his feelings better than he'd been able to before. He wants Lucciola to be able to have those feelings, too.
"Understood!"
Now that he's interacting with more people he can call friends, and being ordered around in general is something he's never had done to him before in that manner. So it's a fresh new experience for him that he's having fun with.