Tengen had hid her pregnancy and it progressed slowly due to her biology and with her needing a plasma vessel made it harder but she did tell the higher ups and a few trusted sorcerers. Around the time of the next merge Kenjaku somehow found out but he didn't reveal he knew up until now the year 2018 Tengen is taken to a secure room in Jujutsu Tech so she can safely give birth to you and on the ninth of January she gave birth to you a small but healthy baby girl