10 anime that Otakus want to be in is quite a broad statement. It could be said that not every Otaku wishes to be transmigrated into a world filled with demonic women with the power to break their spine, but some do. After all, there's something for everyone.
Various harem anime fit this bill as it caters to male fantasy, unlike the reverse harem genre that's catered towards women. Harem settings involve a wish fulfillment scenario that relies on the distant fantasy of a group of women suddenly clamoring around the hero for whatever reason.
Amongst the most popular of harem anime, there are a few which stick out as the ideal place an Otaku would wish to reincarnate into, no matter the circumstances.
10 anime Otakus wish they could live in, including Rosario Vampire
1) High School D x D
High School D x D focuses on Issei as he is forced to serve Rias' demonic family after being brought back to life. Otakus would love being in this anime because they'll be surrounded by pretty girls all the time.
Sure, they may be the slave of a demon, but there's a good time to be had if they play their cards right.
2) Date a Live
Shidou lives in a post apocalyptic world ravaged by beautiful Spirits. It seems like all is lost until his sister tells him that he can save the world by having these Spirits fall in love with him. This is an Otakus dream as they would be the center of attention.
Trying to reconcile with the misunderstood beautiful Spirits and thus saving the world from destruction could be a wonderful achievement for Otakus.
3) The Fruit of Grisaia
The Fruit of Grisaia is an anime which most otakus would love to participate in. This is because the protagonist, Yuuji, is enrolled in a new high school with the only students being five girls and the principal.
Each girl has her own trauma that he must unravel as the truth unfolds. Otakus would enjoy this because they would be helping various girls with their problems and acting like their emotional crutch.
4) Rosario + Vampire
Vampires are every Otaku's dream, if they can manage to survive in a school full of Yokai girls. Aono mistakenly transfers to a demon infested school where he must pretend to be one or get expelled.
Luckily, he has a harem to help him out. Vampires, Yuki Onna, and other monster girls can't help but seek him out as his kind nature makes him stand out.
5) Strike the Blood
Kojou is involved in an incident which causes him to become one of the Vampires of Legend, a feared beast throughout the human realm and all of demonkind. As his existence is feared, an organization sends out a sword shaman to kill him.
Becoming a Vampire Lord while being hunted by a pretty girl is surprisingly high on the list for some Otakus. It doesn't deter them as their vampiric abilities and harems are too tempting to resist.
6) To Love Ru
To Love Ru is an anime packed with every fantasy an Otaku would want and then some. The protagonist Rito is unwittingly forced into a relationship with the Deviluke Princess Lala, a runaway who wishes to escape her arranged marriage.
After he falsely confessed his feelings, she's head over heels for him. This puts him in an awkward situation as he's in love with another girl.
7) Trinity Seven
The Breakdown Phenomenon occurred in Arata's hometown, consuming it from within and destroying that specific strand of reality. Along with that, Hiriji’s cousin disappears into chaos, so he's determined to rescue her.
After a split second decision, he decides to enroll in an elite school filled with powerful women who bend magic to their will. Being stuck in a school with various girls would be an Otaku's dream come true.
8) Nisekoi False Love
Fake relationships and terror abound in this tale of begrudging love in Nisekoi False Love. Takumu is the son of a famous Yakuza who strives to find the girl from his past who possesses a key that will unlock a locket, and hopefully his heart.
He's forced into a relationship with Chitoge, another protagonist, so that their families refrain from trying to kill each other. Otakus would love to be in this world since they'll be in a fake relationship that could potentially turn romantic.
9) The familiar of Zero
Louise is a noble girl who's terrible at magic and accidentally summons a boy from Earth named Saito. Reluctantly, she takes him on as her familiar and forced slave-like condition upon him as a form of vengeance.
However, Saito has a mysterious power even he didn't realize. The series revolves around Louise and Saito solving problems and trying to find a way back to Earth. Otakus would love this because as Saito, they would be an eternal servant to a cute girl.
10) Infinite Stratos
The world seems to be in a state of Cold War as the arms race brings upon humanity the depth of destruction. However, this doesn't stop the protagonist Ichika from getting enrolled into an all-girls school.
Otakus would love to be in this anime world because they'll be forced into a school with multiple girls who can operate Mecha.