Takenaka is originally introduced as an image-conscientious character pushed into the Telepathy Club similarly to Mob. However, once it is revealed that he is a Telepath, he is shown to be standoffish despite his humor and tendency to tease others. He feels lonely given his telepathy and is overwhelmed by the consciousness of society.

Takenaka had previously filled a gap in the Telepathy Club to maintain the minimum number of members needed for the club. He had no interest in the club or in telepathy. He worried about how people looked at him because of his club membership, so he decided to leave the club. As a result of him leaving the club, Tome Kurata had to find a new member to keep the club open. He is later revealed to have joined the tennis club.

In chapter 98 he is revealed to be a telepath. He returned to their former club room investigate the telepathic ringing generated by Mob and Shiratori brothers. He is subsequently recruited to help contact extraterrestrial life, although he only joins out of obligation.

Later, he is revealed to have actually memorized the summoning formation and incantation despite knowing it to be a hoax, as he didn't want to ruin their memory. He proceeds to spend his New Years' with the others after successfully coming into contact with alien lifeforms.
(Source: Mob Psycho 100 Wikia)