Coming from a mostly unknown background, it can be implied that Strade has a number of psychological issues and fascinations. He is charismatic, a trait which many find very compelling. It can be implied that this trait, that many killers like him share, is his main device in luring victims.
As for his tendencies, Strade is a by the book definition of a sexual sadist. This implying he finds sexual arousal in making others suffer, which can also be seen in a number of his endings.

German psycho!

Personality
As stated in his official description Ren for the most part is a charming, sweet and gentle person however he tends to be both clingy and violent sometimes as a result of his experiences with Strade. Ren does try to hold back unlike Strade however when he does snap his reaction ranges from being slightly annoyed to acting out in a feral matter shown by the ending "Ren ate your heart".

Traumatized Fox!

Reverse!Au Traumatized Fox

Behaviour
Sophisticated and charming, Rire outputs an aura of power and elegance. His pleasing physical appearance and gentlemanly demeanour usually enchants or commands people. Realistically, he is extremely manipulative and sadistic, among other things, and finds entertainment in the reactions of other people. Humans are particular his favourite, as their reactions are more unpredictable.

Quite polite demon!

Behaviour 
Lawrence feels like an outsider to the human race and finds other people to generally be dangerous and untrustworthy. Either they’re a nuisance, or dangerous, or lying. At his best, he’s a loner who wants to be away from society whenever he can, but he’s also quick on lashing out at any person who interacts with him. He relates people to pretty flowers who lie to get what they want. Lawrence is generally withdrawn.

Reverse!Au Weed Guy!


Sano seems rather cold when you are first kidnapped. But if you get on his good side, he'll warm up.
Sano likes to feel in charge of a situation and like he has power over his captives.  Cooperation from a victim is appreciated and often rewarded.  However, Sano also wants his captives to last as long as possible and when a captive makes a reasonable request, he's likely to fulfill it should the victim have been cooperative up until that point. 

Depressive japanese!

As there are supernatural things involved with Jason, he does however have a personality being that of a child along with being very wrathful. Jason was also known to grunt when injured heavily. He loved his mother dearly as she was the only person that showed him true love in his childhood.

Yandere Jason!

A fallen Angel with an affinity for Demons. He's sadistic, romantic, but easily bored. He's an ancient being with a chaotic agenda. Earning his respect is very difficult.

Fallen angel!

Behaviour
Akira is a very cocky, confident seeming individual with a rather rough exterior at first. In later parts of Sano's route, it is seen that he is rather bold and straight-forward with the player and quick to trigger.