A humble male student who is a member of the school's Swim Club along with his friend Saaya Minato, Daisuke is quite concerned when Saaya unexpectedly quits the club. Unknown to Daisuke, Saaya harbors a wild obsession about being with him, but has a hard time controlling herself around him.
A typical average male student at school and the best friend to the beautiful Saaya Minato, Daisuke Takagai takes great pride in supporting his friend and being an active member of the Swim Club with Saaya. He is totally oblivious to the fact that she harbors powerful feelings of love for him, and is quite surprised when she confesses her true love and desires to him in a sexual manner at school! Once he realizes that she loves him, he finally rises to the occasion and becomes her loving, supportive boyfriend.
Daisuke Takagi was originally created by Takeda Hiromitsu for use in the Tsundero hentai manga, and it is not fully known as to what exactly inspired his creation. Daisuke first appears in Tsundero #1 inside of Chapter Five (Milk Princess).
Being a character from a Hentai-related manga, Daisuke does not undergo any major changes apart from stepping up to the plate emotionally after his friend confesses her true feelings for him and becoming Saaya's supportive boyfriend.
Frustrated by the constant remarks and looks aimed at her, coupled along with her struggles to keep her feelings regarding her friend Daisuke a secret, Saaya decides to leave the club in order to get away from the negativity, much to the worry of Daisuke, who is concerned by her recent behavior and seeks to help her in whatever way she needs. Chasing her down the hallway, the concerned Daisuke tries to reason with the flustered Saaya, even reaching out to grab her hand to comfort her, but is stopped cold when she tears her hand away from his grasp and storms off into the female restroom, leaving the worried Daisuke behind. After several minutes go by, Daisuke tries to contact Saaya on his cellphone, but his call to her goes unanswered, much to his dismay. Frustrated, he heads off in order to do something else, leaving his friend behind as she "gets off with herself" in the restroom.
Later in the day, Daisuke decides to practice swimming in the deserted pool building when nobody is around, and when the area is clear, he jumps in and begins his training. While he practices his stroke in the pool, Daisuke unexpectedly runs into someone who has gotten into his way, his hands firmly squeezing his friend Saaya'a breasts before he realizes what he is doing. Freaked out by running into someone in the middle of the pool, the confused Daisuke surfaces in front of her, gasping for breath as he lifts up his googles in order to see who he had just bumped into. To his horror, he finds himself looking at the furious face of Saaya, who has gone into a fit of rage over his accidental groping of her breasts. With a quick forward lunge, Saaya gets behind the shell-shocked Daisuke and puts him into a sleeper hold, trying to give him a hard time over his careless blunder as she asks him if he found her breasts to be nice or not. Still somewhat confused as to what exactly was going on, Daisuke stammers a jumbled response to her comment, before snapping to his senses and realizing that it is Saaya that he has run into.
Several minutes later, Saaya and Daisuke find themselves sitting on the edge of the pool together, with Minato wrapping up the explanation as to why she decided to quit the Swim Club. As Daisuke gives his input in regards to the looks and words that the male members give Saaya, she becomes frustrated with the fact that he has not talked about her "nips" yet. Turning to face her, Daisuke glances down at her massive bust and changes the subject of his conversation, bringing up the fact that her breasts have "gotten rather big all of a sudden", which snaps Saaya out of her train of thought as she turns to look at Daisuke. She is shocked to notice that he has gotten a rather stiff case of the infamous "morning wood", which causes her to quickly turn away in mild disgust as he panics and tries to push it back down. Before she knows it, her body begins to ache with a dull pain, her breasts growing hotter by the second as a odd wave of lust washes over the aching Saaya as Daisuke tries to restart the conversation that had been interrupted earlier. Much to his surprise, Saaya pushes him flat against the tile floor and climbs on top of him, blushing slightly as she demands for him to take responsibility for her actions. Puzzled, Daisuke struggles to put together exactly what she means, but is brought to a screeching halt when she pulls down her right part of her swimsuit in order to reveal her elongated nipple to him.
Losing control of both his pent-up desires and himself, the turned-on Daisuke launches into a rapid oral session with her hyper-sensitive breasts, toying and sucking on each of her nipples as the waves of pure ecstasy begin to wash over Saaya, who has also lost control of herself and finds herself getting kissed passionately by her beloved Daisuke. Deciding to go all out with her efforts to show just how much she loves him, Saaya engages him with a sloppy paizuri session, using her massive breasts in order to help him enjoy as much pleasure as she can possibly give him. Trying to help her along to orgasm, Daisuke redoubles his prior efforts at toying with the breasts, tugging and rubbing her hyper-sensitive nipples repeatedly until they are both close to achieving orgasm together. With one last massive squeeze of her breasts, they both achieve climax together as with little to no warning, a large quantity of breast milk begins spraying out of her stiffened nipples all over herself and the stunned Daisuke. For several seconds, they sit in a state of both confusion and surprise, since it usually means that you are pregnant to have any kind of lactation coming out of a woman's breasts. As the stunned Saaya realizes just what has happened, she snaps back to reality and tells Daisuke that he will be the one that she loves, having decided it back when they were kids. Blown away by her revealing her true feelings for him, the eager Daisuke prepares to engage her in proper sex as Saaya pulls her bottom part of her swimsuit away, revealing her vaginal area to him. Saaya wishes to confirm her feelings for him by allowing him to engage her sexually, and gives him the confidence to begin.
For the remainder of the chapter, both Daisuke and Saaya engage each other in a bout of wild sex, both achieving orgasm one more time as Daisuke discovers that he has had a fetish for breast milk that he never knew that he had. After they have finished, the pleased Daisuke asks her to please become his girlfriend, so that they can officially become a proper couple. Thinking it over for several seconds, the joyful Saaya agrees to his offer, and from that point onwards, the two of them are in a passionate relationship. The next day, Saaya is shown apologizing to the consultant for the Swim Club about her actions the day before, with Daisuke and another boy watching from inside the pool. After clearing herself of any trouble, she makes her way towards the exit of the building, which causes the caring Daisuke to climb out of the pool and rush over to her in order to see if she was ok or not. Saaya tells him that she has been forgiven, but is somewhat flustered when Daisuke tells her that he meant if her milk-swollen breasts were feeling ok or not. Grabbing his ear, she coyly tells him "If it comes to that, I'll let you wring them out a lot later, okay....my darling...". As she walks away humming to herself, the love-struck Daisuke gets a odd expression upon his blushing face, slowly repeating her name softly as both the consultant and the boy he was in the pool with look on in pure shock.
As with the other male characters of the Tsundero manga, Daisuke does not appear in any media or products outside of the main Tsundero manga.