There is a character named Jigen in the Naruto series, but "Dekutoten timeless dimension" is not a concept or location that exists within the series. Therefore, it is not possible to determine if Jigen can enter this fictional dimension.
what about jigen?
Jigen, also known as Isshiki Ōtsutsuki, is a character in the Naruto/Boruto series. He is a member of the Ōtsutsuki clan, a powerful alien race, and serves as the main antagonist in the Boruto series. Jigen possesses the ability to access a dimension known as the "Kamui dimension" or "limbo," which allows him to enter a separate plane of existence and manipulate time and space within that realm. However, it is not explicitly mentioned whether Jigen can enter any other specific dimension beyond the Kamui dimension.
