Julius and Nightmare have a strange relationship. Julius ignores Nightmare, but Nightmare drags him to help him practice. Despite that, Julius doesn't truly hate him. He is just annoyed when Nightmare keeps him away from his work.
Julius and Gray have a poor relationship,even before Alice came. After she came, the relationship became worse. A common argument when Alice is staying at the Clover Tower is that that Alice knew Julius first (and may have even stayed with him), but now she is staying at the Clover Tower, making her Gray's guest instead.
Julius doesn't seem to hold any ill feelings against Blood, despite the fact that he was the one that broke Elliot out of prison. He regards Blood as an eccentric and dangerous person who is also influential in the Country of Hearts.
Julius has a hateful relationship with the March Hare, the Clockmaker had Ace throw Elliot in prison after the March Hare broke the clock of one of his friends. Later, Elliot was broken out of prison by Blood Dupre.
Tweedle Dee & Dum
On good terms with Gowland due to Julius being the only one who doesn't make fun of his first name.
Julius thinks that Vivaldi is a cruel woman and stupid to the point that it exceeds reason.
Julius hates Peter and considers him nothing more than the Queen's pawn.
While Ace considers Julius his best friend, Julius doesn't agree. However, he is shown to care quite strongly about Ace, as much as he may deny it, and despite how much he scolds the knight, Julius acts as a sort of older brother figure at times.
Like all other role holders, Julius does not like Joker. Even so, he has to act civil with him on occasion as Julius and Joker have to work together as administrators.