Ryu Shinjo is a student who is invited (forced) by his best friend to enter the world of virtual and online role-playing games (VRMMORPG).

During the game and when choosing his class, Ryu decides to become a "priest", through which he can regain his health through magic and thus play alone. However, his playing style is far from what you would call a "normal priest". It is time to learn the story from Ryu, the priest who instills terror into anyone who dares to stand in his way.

not Onee x Shota

p.s if I put romance tag, I'll got bullied

From MangaHelpers:
A new program has been set in place for a certain area, where children are separated by gender into eastern and western territories. They're raised with no contact with the opposite sex, and made to only focus on their studies. Of course, there are a few bad apples, and the worst of these are sent to a co-ed school with the troublemakers from both sides. Unfortunately, this school soon became known as a place where the teenagers would battle to determine who was the strongest, and many boys and girls tried to be sent there.
At this school, the girls have an advantage, since the boys mysteriously get nosebleeds whenever they look at them. However, the strongest girl, Jun, is shocked to find that the strongest boy, Kyo, doesn't get a nosebleed when he looks at her! It turns out that both of them have had some experience with the opposite sex in the past, and they both have embarrassing secrets in the present.

A hero is made of H (ecchi) and Ero.

A talented young cook's encounter with a hungry girl who popped up in his kitchen changes his ordinary life forever. Dora, a summoned spirit and a truly cute goddess, now calls him master. However, he is not interested at all and trying everything he could to get away from the ghostly figure. As fate would have it, when he becomes a summoner by accident, there is no turn back in life.

In Alternative, Takeru wakes up three years after the end of Unlimited to find himself back in his room. Although he first thinks that everything that had happened to him was a dream, he soon feels that something is wrong, and leaves the house to find that he has been sent back in time to the beginning of the events in Unlimited. Unwilling to accept something like Alternative V, he decides to help professor Kouduki to complete Alternative IV and save mankind.

After the Hero’s birth, Seycred, the youngest priest of the church is sent to take care of an abandoned chapel right across the Demon King’s Castle, for it to serve as a resting place in his quest. Thus, begins the relationship between a priest and the Demon Lord. Was the person with the right ability sent to the chapel or will their encounter bring forth chaos to the nation?

The Cheerleading Club is trying to recruit the last remaining member of the Rooting Club. Expect an excess of school spirit and fanservice.

In a little town near Osaka, an old tradition is being perpetuated. Every year, for hundreds of years, the men of the town defy each other in the “grand ceremony of Masuraou”. Their weapons? Their courage and their fists! Their goals? Becoming the king of the town!

It's in this atmosphere that Takeshi Yamato, a young high schooler from Tokyo, moves in. Ex-gang leader decorated with an incredible secret, he is decided to forget the past and become a socially acceptable guy... However, between his secret being found out, the fights, the girls and the messing up with his friends, he is far from becoming a model high schooler!

Funatsugi Maki is in love with a girl, who happens to have a voracious appetite. Little does he know, despite acting as normal as any middle-high-school-aged girl, she's actually an eldrich horror in disguise. Psychological horror and romantic comedy shenanigans ensue.

Suou Shuuichi is your typical otaku neet. But what happens when his latest figurine order turns out to be something completely out of this world.

Hirano Hii is a school girl that hates big boobs, being a pettanko (flat chested) herself...or does she? Together with her friends, Ooki Mayako, Hii's childhood friend that is a cheerful genki girl lacking on the studies department, and Tamai Yukina, Hii's polite, corteous and kind friend that sees that there might be something else to her hate of breasts. In their school, they go through various day-to-day situations concerning their youth, whatever lies in store for them, and get involved in a lot of antics involving their breasts, packed with carefree humor and a lot of borderline ecchi situations!

Kanzaki Hajime, overwhelmed by urban girls. He then changes his mind, come back to his hometown Hoshihime village, but the girls in that village also...!?

Myeong-In, a student at a third-rate university, doesn't get much support or respect at home. But his true identity is a professional online gamer who is famous and rich, a star gamer nicknamed "God of Game".

Suddenly, three beauties intrude into his double-identity life. And Myeong-In learns a shocking truth from them: the elites of society play something called "Game of Gods". If you win, you receive superhuman abilities and powers, and you can basically rule the real world!

A reincarnator, Dahliya, taking advantage of her broken engagement, “I won't hang my head any longer” made firm her resolve.

Now using her beloved magic devices any way she wishes, the fun times keep rolling in ―?!

Kazuma, a highschool student who loves eroge, has been confused by the honour student and beautiful girl, Misaki Honoka, who's the school's prodigy. What's more, Honoka had declared that she would try her best to become a "heroine" that Kazuma likes?! "Can you..... train me?" What kind of eroge is this?

Just when Hyuuma Tadahito had finally received a job offer from a publisher, he was hit by a truck. But when he woke up, he was in a publishing company in a world where he was the only human! Now he will have to get used to his new working life in another world...!

Popular junior high school graduates, Mirai & Satsuki have moved on to their 2nd year of junior high school. But what happens when they are trapped between a big-tittied beauty teacher, a scary and beautiful classmate, and a rival appearance? Is this the premonition of a big upheaval? The much-awaited sequel to Schoolmate begins!

When evil aliens arrive on Earth, seeking its destruction, it’s up to the planet’s kaiju monsters to save the day! But things aren’t exactly as you’d expect… These kaiju may be adorable young women, but they’re no less ready to kick some alien butt!

From AnimeCouncil²:
This story revolves around the life of Akira, a man who has been saving his money for over three years to finally obtain a computer. Unable to get the computer model he wants he is offered the same model from a shady man in an alley. What happens next is something that will change the life of Akira forever. For he didn’t look at the box closely enough to note that it isn’t Model 9821, it is actually Model 2198, a super advanced gynoid who’s sole purpose is to serve and protect her “master.”