Guren was a powerful, I mean crystal release? She was arguably stronger than the Sound Four. WHy didn't Kabuto bring her back to life when he was the one that killed her? He had her DNA.
Guren was never killed (Though unable to perform any hand signs (with her hands busy holding back Rinji's arms), Guren still managed to use the Crystal Release and crystallized herself and Rinji. The two fell into the water below. Gozu later saves her.), in fact, she is even seen later in Naruto Shippuuden:
After the final battle between Naruto and Sasuke, Guren, Yūkimaru, and Gozu can be seen in the crowd at the entrance to Konohagakure.
Guren couldn’t be reanimated because she didn’t die she crystallized her self and in many cultures, movies and books crystallizing or cryogenic freezing keeps the person enters into a stasis meaning they can’t die because all the nutrients stay still meaning she can’t die from male nutrition because the nutrients never left her body
Simply because Guren is a filler character. If she was reanimated, she wouldn't be able to kill any major characters in the war, such as Mifune. Its either shes reanimated and kills no people, making her utterly useless, with no point of even reanimating her, or she kills only filler characters, I guess.