Have you ever watched The Conversation? The movie’s main character is textbook paranoid:
[Harry] Caul is obsessed with his own privacy; his apartment is almost bare behind its triple-locked door and burglar alarm, he uses pay phones to make calls, claims to have no home telephone and his office is enclosed in wire mesh in a corner of a much larger warehouse. Caul is utterly professional at work but finds personal contact extremely difficult because he is intensely secretive about even the most trivial aspects of his life. Dense crowds make him feel uncomfortable and he is withdrawn and taciturn in more intimate social situations. He is also reticent and obsessively secretive with colleagues.
Mutsuki Chiharano from Type-0 is also a textbook paranoid:
Paranoid Personality Disorder. The essential feature for this type of personality disorder is interpreting the actions of others as deliberately threatening or demeaning. People with paranoid personality disorder are untrusting, unforgiving, and prone to angry or aggressive outbursts without justification because they perceive others as unfaithful, disloyal, condescending or deceitful. This type of person may also be jealous, guarded, secretive, and scheming, and may appear to be emotionally “cold” or excessively serious.
Despite being brilliant, she’s irrationally suspicious against her classmates with little evidence. She believes her classmates are out to get her. So she still holds a grudge against them, building bombs (and occasionally detonates them) to ward them off.
Mutsuki is a genius inventor of Class Twelfth and keeps a supply of homemade bombs handy. She has a paranoid personality and is trigger happy with her bombs, causing many to avoid her.
But for whatever reason, she and Ace may have had a thing. At least, that’s the rumor…