|Doom Dome Battle|
|Warriors of Babylon|
|Demon Bounty||Mission Alpha|
|Call of Cthulhu|
Mai Waifu is a character in the Doom Dome Battle appearing playable in the first two installments and appears playable once again in Warriors of Babylon. She has a huge, one-sided, crush on Joshua Tamashii. She was turned into a witch by the end of the first game by defeating Bavarian.
In the first game Mai is a quick fighter wielding a large knife as weapon. She is agile and quick in dodging and attacking. She deals quite some damage as she can pull off long combo's that can keep the opponent staggering inside of them. She does counter stabs, throws daggers, hack with an axe and ocasioanlly even dropping a bomb for total chaos.
When she was turned into a witch, certain things changed for Mai. Because of her chaotic nature she obtained dark magic, but still holds dear to her knives. She now also throws her daggers with dark magic, stun opponents a second and summoning dark hands out of the shadows from the ground. When she hacks down her axe she now instead breaks the ground and darkness erupts from the crack in the ground.
Her Doom Attack is Yandere Mode which actually differs in the games, but retains the same name. In the first game she gets a real psycho look in her eyes and rushes at the opponent with a hatchet and slices them multiple times. When it KO's them she grabs another knife which she stabs through their head and continues stabbing when their body is still on the ground, afterwards looking up covered with blood on her face.
In the second game she levitates in the air and levitates chunks of concrete with dark magic and throws them at the opponent. When it KO's them she summons a large sphere of darkness which she drops down on the opponent, their body splattered across the ground and blood on her face as a manical grin appears on her face.
Relatively little is known about the past of Mai Waifu. The whereabouts of her home situation is ambiguous, only that she has a troubled upbringing which resulted that she was thought the wrong concept of love. What is known is that during high school she developed a crush on Joshua because he cheered her up once when she was at a really low point in her life, and now wants to make it her life's work to make Joshua's hers.
Doom Dome Battle
Mai was inside of the school when suddenly a part of it collapsed, after that had happened she got out and tried to find Joshua to make sure he was safe. She eventually caught up with him at his uncle's house where she interrupted the fight between Joshua and Mephistopheles to keep Joshua safe. Mephistopheles got away and they saw a large UFO appear. Amaya wanted to take Joshua away, but Mai wanted to protect Joshua and began fighting Amaya.
Amaya stuns Mai who then blacks out. When she comes to she sees a demon lurking above her, Barbatos who says he can bring Mai to a treasure that will help her protect Joshua. Together they travelled through Wildefort until they encountered Tyrant and Maria Justice, Tyrant wanted to kill Barbatos and Maria allowed it as Barbatos and Mai are injustice. They managed to overpower Barbatos and Mai, which led to them making an escape.
The two make their way to the circus of Bibo the Clown where Barbatos alerts Mai that this is the place the treasure is. They go inside and retrieve the box, but as they leave they encounter Bibo and fight him, after which they escape. They flee and encounter Rokukai, Mephistopeheles and Prince Bucksalot. It is revealed the box contains Lilith and Barbatos reveals it will make him the ruler of Hell. Mai feels betrayed and a battle starts between Prince and Barbatos while Rokukai opens the box. Lilith appears and takes Rokukai to the Illuminati HQ, Mai and Prince follow them.
When Mai entered the building she saw that the Illuminati God, Bavarian, had appeared. Giselle wanted to have the powers of Bavarian, but Mai interrupted she desired them as well. Bavarian would grant it to them if he was defeated in combat. Giselle and Mai teamed up and defeated Bavarian, and becoming witches. Giselle offered Mai a place in her coven, which she declined. She said she needed to go to Joshua, thus her and Prince went to meet up with him and the others and found out he was okay. She joined everyone in the battle against Soluna.
Doom Dome Battle 2
Mai reappears as a playable character in the second game, trying to win the heart of Joshua, but gets involved in some pretty dark magic.
Warriors of Babylon
When Mai discovers that Joshua has been beamed up to the Hanging Gardens of Babylon she wants to go and save him. Yggdrasil denies her passage to come along with her, but Mephistopheles is indifferent about it and actually needs Mai's magic to get the portal working properly. Together they go up to the gardens and Mai begins her search for Joshua.
- She is based on Yuno Gasai from Mirai Nikki, in terms of her obsessive stalking and yandere behavior.
- The name Mai Waifu is based on an NPC who appears in Yandere-Simulator.