Queen War -YBI Plan-

Queen War -YBI Plan- (正妃戦争-YBI計画-) is a game event that occurred in Mass for the Dead. It was released on June 3, 2020 to June 15, 2020. The event was re-released on May 10, 2021 to May 17, 2021.

Background
The Trial of Love. Momonga is testing her love. Convinced by that, Albedo devises her own plan to challenge the trial. Even Shalltear's plan, which did not reach the condition, the pure white devil who wants to fulfill love all at once completes the YBI plan.

Incident
The Trial of Love that Shalltear Bloodfallen has divined as a secret test that Momonga wishes to test his two potential suitors reaches Albedo who has been devising her own plan to challenge the draw outcome of the Queen War. While Shalltear's method to gain Momonga's love failed, Albedo is determined to succeed. To assist her she solicits the aid of the protagonist and Slimeko at Ashurbanipal. Seeing her in their sanctuary, the two suspect that Albedo wishes to complete the Trial Of Love which is now mute as Momonga has declared it to have served its purpose. Though Albedo says otherwise and wants to partake in it using her own plan which has been titled as "YBI Plan."

Momonga who has been reading a report concerning the possible existence of players in the New World. His thoughts are interrupted when a maid on duty to serve him comes into his study. Without looking up he allows her entry, occupied with the idea of giving the maids holidays. It is only when the maid invites herself to him does he realize who the maid is. Albedo now wearing a maid outfit much to Momonga's shock. Confused as to why the Overseer Guardian is in a maid uniform, Albedo explains that he had given her permission a few days when he and her were discussing the frequency of missions outside of Nazarick. Besides Solution Epsilon, the protagonist and others the two found that they were facing a shortage of help as there were some tasks that the general maids cannot do on their own. That being, handling security and cleaning work on the 10th Floor which has become extremely dangerous. Usually the Pleiades are assigned to such tasks, but Momonga does not wish to overwork them and wants to find an alternative solution to alleviate the woes of the 10th Floor. When Albedo states that she has an idea, Momonga accepts it without question, trusting her to handle the details. The result of his hasty decision now has caught up to him in the present and he finds that Albedo took it upon herself to serve as a maid to handle the 10th Floor upkeep. She makes two reasons for her presence in substituting as a maid. One is to experience the daily maid operations and the second to review the work efficiency of the general maids and Pleiades. Her reasoning convinces Momonga, especially when she suggest in providing an opportunity to reward the dedicated maids.

Albedo then begins working as a maid in Nazarick as well as doing her duties as an Overseer Guardian. In the Round Table Room, Albedo is being instructed by Yuri Alpha and Lupusregina Beta on the proper way to make tea and drink it. Albedo assures them while as a maid she will be considered their junior.

In the Lemegeton, Entoma Vasilissa Zeta and CZ2I28 Delta are cleaning and guarding the area. Shizu gets into a brief argument with her sister, noticing that the Arachnoid came back from the Black Capsule for a snack, scolding her for eating on the job. Entonma points out that Shizu does so as well, and points out that her cockroach is small and convenient. Albedo soon arrives and politely tells them to not fight while on duty. She compliments them on the cleanliness of the room, which the maids agree as the Lemegeton and library are among the areas that have been repaired. Shizu though wishes to clean the Throne Room, but due to circumstances of the Crack it is too volatile and dangerous. Albedo then joins the two maids in "cleaning" the Throne Room of Chaos Beasts that are scheduled to emerge from the phenomena.

Later on the 6th Floor, Albedo finds herself working with the general maids harvesting the crops in the fields. Though the Overseer Guardians read the reports of the maids' tasks, after doing them see finds that they are busier than believed. Foire states that the workload isn't too bad as they still have a lot of free time compared to Albedo. Albedo offers to add some "leisure time" to the schedules so that they do not overwork themselves which the maid takes into consideration. Aura Bella Fiora comes around and notes that Albedo really looks like a maid now. Narberal Gamma is appreciative towards her superior in assisting the maids. The dark elf is curious that Albedo is now getting familiar with the maids, and she is proven right as Albedo is secretly using this opportunity to further her own agenda. Being a maid gives her the perfect bride training program to serve Momonga. Narberal and Aura plan to head to the Crack on the 6th Floor to quell the Chaos Beasts which Albedo invites herself. Shalltear Bloodfallen and her two Vampire Brides also arrive to the campaign and are shocked that the rumor of Albedo becoming a maid is true, but vampire suspects that Albedo has an ulterior motive.

Back in Momonga's study he is working at his desk, while Albedo cleans the room. At one point Albedo request two Eight-Edge Assassins on the ceiling to make room so that she may be able to clean the area. Momonga watching her finds the whole experience new but not uncomfortable. Even Sebas Tian praises her work with a passing score, making Albedo's presence among the maids and staff to be accepted. However there are some exceptions, being Shalltear.

While in the Throne Room, she slays all the Chaos Beasts that have come from the Crack. After the extermination is done, Demiurge tells her that he will handle the collection of the Chaos Stones as he knows she is eager to be somewhere else. Shalltear quickly then departs and finds her target, Albedo in the hallway of the 9th Floor. While Albedo greets her in an innocent manner, Shalltear is not fooled and demands to know what she is up to. Albedo coyly states that she has no idea what the Floor Guardian is talking about and excuses herself. Once the Overseer Guardians departs, Solution Epsilon joins Shalltear who has been observing Albedo at the latter's orders. The other maid can find nothing out of the ordinary other than Albedo being resourceful as a maid, but Shalltear insists that something is going on. Solution shares her concern, noting how her sisters have taken an interest in Albedo since she returned to Nazarick. Shalltear suggests maybe that they are under the influence of mind control or a magic item, but the maid doesn't believe that is the case. Still knowing very little Solution promise Shalltear to get to the bottom of Albedo's plot by talking with the other Pleiades.

At the room shared by the Pleiades members: Yuri, Lupusregina and Narberal, they welcome Solution back. The slime happily greets them and they chat, with one of the topics being Albedo's skill in being a maid. The others state that Albedo is quite competent in housework. Other than that they don't seem to find anything wrong with her abilities, though she she seems to be working her hardest while serving Momonga making Solution suspect Albedo is using the maid work as bride training.

In Ashurbanipal, Slimeko and protagonist talk with Albedo, who is pleased that everything is going according to plan. Soon the most critical part of Albedo's plans will come to pass. However Albedo main concern is Shalltear's potential interference.

After some time, at a regular meeting Demiurge reports that ever since Albedo has been added as a maid to reduce the Homunculus Maids' burden, work efficiency has been beyond expectation and a great source of motivation. Albedo is nothing but the source of praise to inspire a competitive spirit amongst the maids. Albedo humbly states it to be nothing and that they should turn to the Pleiades who are all eager to improve themselves. Momonga is happy with the results as since she became a maid it allowed for the generation of extra time for the maids to enjoy. Albedo proposes to help improve the Pleaides' combat abilities by hosting a raid training. Her reasoning for this training is to help strengthen the security measures of the 9th Floor. Momonga sees no issues on it and gives her his approval.

The training is announced to Sebas Tian, the Pleiades, Pestonya Shortcake Wanko, Foire, the Eight-Edge Assassins, Achu, and Unchu. Yuri leading the discussion informs her colleagues that the training is to simulate a scenario where an invader infiltrates the 9th Floor when the Floor Guardians are unable to respond. The exercise will test their skills in handling such a situation. The attacker's target will be a Momonga Plushie made by Albedo. The people gathered currently will do everything to prevent that to ensure its safety. Albedo assigns Achu and Unchu to guard outside the doors to Momonga's apartment while the Eight-Edge Assassins stand guard in the office of the apartment. The Pleiades led by Sebas will be in the hallways patrolling the area. Yuri reminds everyone that a single hit by either side will be regarded as being "dead". Pestonya will also arrange for the general maids to evacuate the area for the exercise.

At the time of the training exercise, Lupusregina is getting bored and wonders when they will be on break. Narberal scolds her for her laxity, but Lupuspregina complains nonetheless. However she fails to notice that there is a shadow behind her. Yuri immediately tries to warn her, but by the time Narberal and Lupus check it has vanished. Solution comes and sees what the commotion is but Yuri spots it again and the two pursue it. It's revealed to be an Einherjar and before they know it they are hit and taken out when it gets behind them. Shalltear in her armor is the attacker for the exercise. Her participation as she believes is most likely part of Albedo's plan to beat her and appeal to Momonga, but Shalltear has no intention of being the loser and vows to defeat her rival.

Shizu and Entoma are worried that they lost contact with their sisters and decide to report it to the others at the doors of the apartment. Sebas and the others report they have not seen anything but soon receive a report from the maids that something is attacking them from the left and right corridors forcing the Pleiades to separate to confront each threat. Vampire Wolves soon emerge to attack the defenders. Knowing that these summons could only be one person, the group notice Shalltear's sudden appearance after she drops [Perfect Unknowable]. She gets past the insect guards and into the apartment. There she immediately attacks the Eight-Edge Assassins present there. While the Pleiades and guards are occupied with her summons she targets the Momonga Plushie. But first she decides to remove all obstacles. Just as he was about to hit the last Eight-Edge Assassin, it's switched by Albedo with [Transposition] who then parries the Floor Guardian's attack with 3F and hits her thus allowing the Overseer Guardian to claim victory.

At the Round Table Room, all participants are gathered while Momonga hails as a success especially due to Albedo's quick thinking. Shalltear is not impressed though. To her surprise rather than take offense Albdo praises her progress in cutting through all the defenses. Still suspicious Shalltear accepts the praise. Albedo asks Momonga to allow the raid training to continue, though under unannounced conditions to heighten everyone's preparedness. Momonga and the others have no issue and accept the plan. In Ashurbanipal Albedo visits her accomplices to tell them that the plan was a success and now she has removed all obstacles to her goal thanks to Shalltear.

Some time after the raid training, Shalltear is in the Mine Dungeon controlled by Abyss Demon assisting him in clearing out the monsters that are infesting the mine. Together the two go through the mine on a carnage spree wiping out anything that opposes them all the way to the altar. Shalltear still thinking about what Albedo is planning wonders perhaps she may have been paranoid as all Albedo has done has improved the efficiency of the tomb. Meanwhile Albedo pays a visit to Pandora's Actor in the Treasury. The Treasurer hands Albedo certain items that will give her support and resistance effects. When Shalltear reaches the prop altar in the mine she receives a message from Solution reporting Albedo's true plans. Upon learning of what Albedo is up to, the vampire seethes in anger and flies out of the mine much to Abyss Demon's confusion.

On the 9th Floor of Nazarick, Albedo is humming to herself. Foire seeing her superior in a good mood greets her which the later agrees that it will be a wonderful night. Later she passes the Pleiades maids in the hallway, Yuri noticing a distinct scent on Albedo, compliments on it pleasing the latter. Albedo explains that she is the one serving Momonga this time thus she wants to look impressive. The Overseer Guardians approaches Achu and Unchu at their post and they allow her entry into Momonga's apartment. Stepping into the study she then changes her clothes to prepare for her special night with Momonga.

Momonga in his bed chamber is disturbed when Albedo enters wearing a night camisole. In an instant she rushes towards him. Momonga uses [Time Stop] to freeze time, but to his horror finds that the spell has no effect on her as she has taken measures to ensure he cannot escape her. The [Time Stop] soon expires and the Eight-Edge Assassins are stunned at the madness Albedo is projecting. Albedo no longer disguising herself lustful intent insists this is a raid training exercise and proceeds to hit guards.

The cries of the Eight-Edge Assassins attracts Achu and Unchu who come in to see what the commotion is. Hearing that this is some sort of unscheduled raid, the two play along and are incapacitated. Now alone with Momonga, Albedo proceeds to straddle him on the floor. Her entire plan had been to use physical force to get Momonga's love rather than Shalltear's use of words. Ignoring her master's protests she prepares to enjoy herself but is suddenly pushed off of Momonga by Shalltear's "Negative Impact Shield". Albedo is enraged that Shalltear has interfere, given that she is suppose to be in the mine. Momonga recovering from his dignity demands to know what is going on.

Aftermath
It turns out that while in E-Rantel playing her part as an adventurer, Solution interrogated Slimeko and the protagonist on Albedo's plan. Though they intially remained silent, Slimeko was the first to cave in after the older slime used Momonga's authority to compel her.

In the present Shalltear explains Albedo's ulterior motive to Momonga and the rest. The efficiency and raid training exercise were a means to get close enough to Momonga to complete the "Trial of Love". Momonga is has angst at how the events turned out. Albedo is unapologetic of her actions only imploring to Momonga to answer if she complete his "Trial of Love." Momonga having forgotten the trial is confused on what she is talking about. To cover for himself he states that while he did suffer some embarrassment Albedo's selfishness actually helped benefit Nazarick and thus he feels no regret. Albedo touched tries to cuddle with Momonga but is batted away by Shalltea who proclaims that neither have achieved the "Trial of Love" and thus are still in a draw. The two get into an argument whilst Momonga still throbs his mind over what the trial was about.