A Devil who was expelled from his original world now travels from world to world to get stronger and get his revenge. 

The devil of the Flame World

Rigatona was much bolder and brutal compared to her reincarnation, somewhat justified by warring states. She is usually seen smiling sinisterly in the illustrations she has appeared in.
An angel fighting a bloody war of angels against demons. 
Elite Soldier/Strong as hell. (Way more than a human at least)

Loyal and sadistic warrior.

Subaru Natsuki from Re:Zero in his version of "If History Tsugihagu". 
He lost his memories and after reading Meili's book of the dead, he got the idea to kill everyone who knew him and see their memories in order to make the real Subaru Natsuki come back.
He has Shaula as a companion, who he will ask her to kill herself at the end, to get her memories.
He is willing to pay any price to become the real Subaru Natsuki again. He kills anyone who knows his name. Schizophrenic, talks to himself.

Subaru Natsuki from the If History Tsugihagu.

His default demeanor is innocent and friendly; he believes the best of everyone around him, even (to a point) his enemies. Many of the other characters remark on how naive and hopeless he is. Ein is quiet, usually speaking at times when necessary. He is said to be perverted, however this is usually mistaken though the player can make Ein as such. Ein wears a blue cloak and wears blue shorts, and has brown hair. He also wears brown gloves, and has brown eyes. He appears to be 16 - 17 years old.

Grim Angel

comes off as a solitary, hardworking, and impassive individual. He is staunch to the Gray Garden's god and devil pair. He does what he pleases and exerts authority over both colleagues and superiors; He tends to his flowers religiously and knows how to bake and cook, one of his favorite dishes being ochazuke,is a good chef.is not exactly the type to fall in love. However, if this were to happen, he may act very odd. said to be level-headed, serious, and a doting older sister.

Female Wodahs 

Luna is a little girl who wears a black dress, has long hair and skin as white as the moon,dark blue eyes having dark circles,and wears a blueish gray waning moon necklace. Luna has a favorite book, the same one having a black cover, with a drawing and symbol of a white waning moon in the center with trees on the sides, everything being white to highlight, the cover and back cover probably have similar symbols. The book however is cursed, and can be used to seal someone inside for all eternity.

A seemingly cute little girl with a special book

Yosaflame had "cold eyes," and appeared to be serious unlike his reincarnation. Fought alongside Kcalb in the Great War and died while doing so. Had short green hair and two long bangs with pink layers underneath them. He also had light red eyes, red-rimmed glasses, and raceless white skin. He wore a white dress shirt, black suit, black tie, and gold earrings. He had pink horns with the shape being somewhat similar to Kcalb's as well. Had bad eyesight due to Sherbet's ice magic scarring his eyes

Cold and loyal to Kcalb

Touya appears to be calm or stoic at most times. Touya has straight dark olive-colored hair in a bob cut. She also has raceless white skin and dark olive eyes. She wears a pointy black hat with a dark yellow underside and two lamps hanging from the sides. She also wears a dark olive kimono with a slight gradient at the bottom, a dark olive obi, white tabi, and a pair of black zori with yellow thongs. Her kimono is decorated with many yellow sakura petal patterns in different sizes.

A seemingly calm and stoic witch.

Kcalb was apparently "much scarier" before the creation of the Gray Garden and had deep resentment toward both angels and Etihw. Back during the Great War, Kcalb was darker, having given up everything.
Kcalb have longer hair tied into a ponytail. He wore a black military uniform with six diamonds on the front, three gray diamonds on each sleeve, black belt, and large fur-rimmed dark gray coat with some tears at the end. He also wore black gloves, pants, and shoes.

Scary devil who will turn into a Tsundere.

A laid back individual with a sly smile on her face. has a leisurely disposition and accepts situations readily,using it to his own advantage.is also clumsy and not good at completing work in a precise manner. is prone to teasing.and the subject of his lost eye can break her smooth composure fairly easily.will not accept any eye other than his once-own.like to talk about dirty and sexual topics.rebellious. Alela has long gray hair tied in a low ponytail and an ahoge. Eyepatch a dark gray scarf.

Male Grora

Cranber fought alongside Kcalb in the Great War and died while doing so. She was torn to pieces by Rigatona. Not much else is currently known about her past.
He fought alongside Kcalb and the demons in the great war against the angels and Etihw.
Like her reincarnations, Cranber's personality was gluttonous. She also had a taste for disturbing meals. It can even eat people, angels, other demons, insects,etc.
Had long pink hair tied into two pigtails with bat hair-decor revealing spikes underneath

A gluttony and frightening Demon.

Sherbet has been described as very jealous and persistent. He had a creepy personality.
Sherbet fought alongside Etihw in the Great War and died while doing so. Not much is currently known other than that.
Sherbet had short messy light yellow-ish green hair, raceless white skin, and blue eyes with bags underneath them. His left eye is scarred from an injury inflicted upon him by Yosaflame.He wore a dark gray scarf with a gray cross print due to always being cold.
Literally an Angel. Very strong.

Jealous and scary angel. . .

In the Great War, Etihw used to be much colder than her future self. It has been stated in terms of physical strength, Etihw was pretty strong back during their more "extreme period" during the war. Their hair was much longer, extending all the way down to their feet. Their clothing had more detailed diamond patterning, and their diamonds had a pointier and thinner shape. The white hues of their clothing were also more varied. 