Reincarnation in DxD with wishes

(The votes have been counted, and Venelana will be in the harem. I hope this decision is right.)

Theo can now relax a bit more since Tiamat has joined the ranks of his peerage. In reality, Theo doesn't need his peerage, as he's already at the Super Devil level, and even at this level, he still ranks among the top 10 most powerful beings, he has little chance against Ophis and Great Red. According to Theo, Ophis isn't utilizing her full potential despite being comprised of the concept of infinity; she fails to harness it effectively.

Returning to the Gremory Mansion with Tiamat, everyone is surprised to see her. After all, she emits a powerful dragon aura that draws the attention of all the servants. Theo then goes to his father to introduce Tiamat to him.

Meanwhile, Zeoticus is busy with his daily tasks and is surprised to see the dragon accompanying Theo, as Tiamat emits a strong aura herself.

Zeoticus: "Son, you've brought someone interesting with you."

Theo smiles slightly.

Theo: "Yes, let me introduce her. She's Tiamat, the Chaos Karma Dragon, who recently joined my peerage."

Zeoticus is almost dumbfounded; he didn't expect his son to bring someone like her.

Zeoticus: "You keep surprising me more and more each day. I wonder what you'll do in the future. By the way, there will be a ball where rias fiancée will be determined. You have ten days to prepare."

Theo chuckles lightly at this and leaves the room with Tiamat.

After introducing Tiamat to Rias,Akeno and Valerie, Theo retreats to his room. His room, spanning 200 square meters, is as simple as possible. The Gremory Mansion resembles Buckingham Palace from the outside, decorated in red and black inside.

After a long time, Theo lies on his bed, contemplating the future. This leads him to enter his Mental Palace, where he finds the location of the skills from the Tensura. He discovers Gluttony and decides to learn it. Afterward, he explores other things and comes across something called "Transition from Devil to Demon King," which requires the sacrifice of 10,000 souls.

Theo knows where to find these souls and plans to pay a visit there.

He discovers in the book why devils couldn't evolve beyond Super Devil: the system in the paradise, created by the God of the Bible, hinders their evolution to prevent devils from evolving into demon gods.

Before evolving, he wants to see Michael's face. But things must be done first, such as upgrading the Shadow Legion.

Theo finds much to learn but with this little time. Therefore, he decides to try a new method using Space-Time Manipulation.

He visits Valerie, akeno, and Tiamat, finding Rias there looking quite angry.

Rias: "Onii-san, do you have to marry this woman?"

Theo understands why she's upset and knows he must be careful with his words, as Valerie is present, and Gasper isn't. He wants to see how far she'll go with her jealousy.

Theo: "Rias-chan, what Tiamat said is true. A dragon husband can only be chosen once, and she's already marked me. Even if I wanted to, I couldn't just turn her down."

Hearing this, Rias becomes angry but holds back her anger since the fault lies with Tiamat, not her brother. Then, Rias is about to unleash her full destructive power on Tiamat, but Theo stops her.

Theo: "Let's talk about this later. Right now, there's something else I want to ask you. Do you want to become stronger? We must prepare for the ball, and I'll make you stronger by then."

Excited, they all respond, "Of course."

Upon hearing this, Theo creates a new dimension using Space Manipulation, speeding up time inside it with Time Manipulation. In this dimension, one minute outside equals a day inside. He solves the problems of aging and lifespan using Time Manipulation.

Theo then explains this dimension to the girls and decides they should all go there together. Excitedly, he tells them to be ready for intense training because it'll be like hell.

With that, they enter the dimension, which resembles the Time Chamber from Dragon Ball, empty. Theo uses Material Creation to build a house, where food automatically replenishes daily.

After setting everything up, Theo creates new training outfits for the girls. He then says to them, "I hope you're ready because I won't wait for you to be ready."

Theo then creates 20 Shadow Clones, assigning one to train each girl and the rest to train themselves.

One clone attempts to combine the Dismantle technique with Space Manipulation, while another works on perfecting Cleave, a technique that adjusts itself based on the target's energy level to deliver a cutting blow in one fell swoop.

The other clones focus on learning combat skills and martial arts from various anime (to be elaborated on in future chapters).

Meanwhile, the main body focuses on self-improvement.

With 180 days passing in the dimension due to their intense training, the girls have reached a new level. Rias is now in the Middle Ultimate Class, Tiamat has gained better control over her powers, Valerie is on the verge of mastering her Balance Breaker, and Akeno is now more powerful her thunder looks divine.

Theo has truly helped them to reach a new level. Now that their training is complete, they can leave the dimension

(Don't forget to send power stones and leave a comment. I read all the comments.)