Ferloche is a eternal regressor from a timeline where Frey did succeed in tricking everybody and defeated the Demon King Ruby. The ability to regress at will was originally an ability that belonged to Frey, he retried countless amount of times ( while the number was not stated, it can be estimated to be hundreds of millions if not billions of times) in an attempt to get that happy ending for everybody. In his final moments right after defeating Ruby, he got stabbed by Ferloche without being able to say farewell or clear up any of the misunderstandings. There was no happy ending awaiting him or even any of the heroines despite the defeat of the Demon King. Frey's mental state was already on the verge of collapse and all the Retries have taken a toll on his soul. He used his one wish from the Sun God to annihilate his soul from existence instead of revival as Frey knows that if he was to be revived back to the world, he would take out his built up resentment over eons on everyone he cared about and possibly become a calamity.
Frey's soul was sent to the deletion room but the timer stopped at the last second, I can't remember why the timer stopped. but anyways, lots of despair happens with the heroines realizing the truth. Ferloche resolved to undo everything and shoulder the burden that came with regression, told the Sun God to let her inherit Retry. At this point, Ferloche is only driven by one goal to the point of obsession: to give Frey a happy ending. She ended up going through countless amount of regressions for that purpose. This also gave the Sun God time to recover enough power to implement the "DLC", which involve "kidnapping" a Korean dude from Earth who discovered a bug in Darktale Fantasy 2 and making him the hero from 1000 years ago. A byproduct of the DLC was all the other main heroines retained their memories from the 1st timeline where Frey double crossed everybody to get the False Evil system. Ferloche at some point during her regression realize that the key to access the DLC was the 5 enlightenment (The main heroines need to know the truth) and one coincidence (Glare, a little girl who has an OP ability, a bug found by the Korean guy). Ferloche keeps on regressing to try to figure out the timing of fulfilling these criteria's. By this point, she is very mentally unstable from all the regressions (again no exact numbers but it is easily in the millions), she ended up developing split personalities fooling the Demon God and the system without even needing to try. She let her dumb self handle all the day to day tasks, and only during crucial moments or during the night when she needed to plan things by writing in the diary does her true self emerges. She has to do it this way not just to fool the system but also because her true personality's mind can no longer be conscious for long without completely falling apart.
In a way, Ferloche is like the 2nd protagonist of the story, having ability to Retry and also fulfilling a similar to role to Frey and even suffering as much as him. In the current timeline, she is the reason why Kania and Irina was able to figure out the truth so easily. During the Auction incident, Ferloche deliberately led Kania in the direction in which Frey would drop his badge to trigger Kania's suspicion. During the dormitory questline, she fought in a way that would trigger Irina's suspicion. In one of the earlier chapters, Ferloche threw a maid outfit at Frey knowing his gonna make Irina wear it and afterwards went to snap his neck just to fool the Demon God, she did this knowing that Frey wouldn't die due to the one of the system ability at that time. Ferloche also almost always "accidently" interfere with Ruby's plans, and likes to use extra amount of holy power to "heal" her (which only hurts Ruby more since demon gets harmed by holy power instead) while acting completely oblivious.
Ferloche is a hidden mastermind and is the most unhinged character, her PoV chapters are always either hilarious or just full depresso in the WN and is definitely my most favorite heroine of the bunch alongside Serena.
