Ren smiled and said "Nine Tails or his true name 'Kurama'."
When Minato and Kushina heard him, they were surprised and thought he must have known nine tails or it should be very difficult to know that Kushina has nine tails. From the looks of his face they both came to a conclusion that he must have known about Kushina being a jinchuriki.
"You don't have to worry about Kushina's secret Minato, I am not going to break the seal or something."
They both got astonished to the fact that he know their names. Well actually he came up with a plan to avoid their tragedies being repeated. He got his lesson from his mother's situation. He not going to sit by and do nothing when problems come knocking at his door due to him being not strong enough. He would gain their trust and help them. This way he don't have to worry about being alone in this world. And he could train properly with them. He could just live with them and avoid being running into trouble.
"How did you know our name and Kushina being a jinchuriki of nine tails?"
"You can trust Ren, Minato. Nine tails just told me that he needs to talk with us."
"What?Did Nine tails talk to you, Kushina?"
Minato was really surprised at this. You know, nine tails hatred for humans is set in stone. It should be the first time he talked to Kushina. Kushina had tried many times but she didn't get any replies.
"Well, if that then, how are we going to talk with him?"
"Well Minato, we could just enter Kushina's mindspace and we all can talk."
After some hesitation, Minato looked towards Kushina. She nodded to him.
"It's ok."
"Well now that everyone agrees, then I will directly link everyone's mind with Kushina's mindspace."
They both nodded. Ren opened his Rinne Sharingan and focused on both of them. Though he can't use any chakra now, Thanks to Kaguya sealing her eye powers, he doen't need to use chakra. Ren has no idea it would work or not. He knows from previous life that Mangekyō Sharingan can access to someone's mindspace forcefully. Rinne Sharingan is much more powerful than Mangekyō Sharingan. You can say that the later is a degraded version due to bloodline dilution. So, according to theory, the former can do everything that the later can do. Though you need to understand and awaken Rinne Sharingan's potential later. From his mother's words, he knows that no one knows the full power of a fully matured Rinne Sharingan. How to say, it is a legend even among the Otsutsukis.
After trying to use Kaguya's eye powers with his Rinne Sharingan, he knows that, later it would take much time to adapt to the eye than he previously planned.
"Oh well, it's not like I am loosing my power. Sooner or later I don't need mother's powers. If I can gain their trust and become friend with them, especially nine tails, then my plan to unseal mother will atleast be smoother. I don't need to manipulate others like Black Zetsu. I will just watch how Black Zetsu's plan progress and interfere from behind the seen. No need to take risk of getting discovered. God knows what it do if it knows that I am alive. And there is not only Black Zetsu; Danzo, Orochimaru are also individuals,whom I have to be cautious about. If the mad scientist or the greedy fellow knows about my heritage; no one knows what would happen to me. Maybe I will become a lab rat or have my eye plucked by Danzo."
When Ren thought of the consequences, it sent a chill down his spine. Now his body needs another 2-3 years to adapt to the awakening of Rinne Sharingan before he could use all his chakra. He have to start from botton like ninja academy students though having a huge amount of chakra rivaling tailed beasts.
"It seems that I have to talk with spirit of Hagoromo, if I want to speed up this process. Maybe he can help me, his older brother. Though I don't know if he knows about me."
After some time concentrating, the trio was pulled into a dark, gloomy space. They were standing in water. Their surrounding was covered with pipes which extend to a tunnel. The three of them looked at each other and nodded. This is the first time Minato entering Kushina's seal where nine tail was sealed. Though he didn't show it, he was nervous and somewhat anticipating about their meeting with nine tails.
"Ok now everyone has entered my seal, just follow me through the tunnels."
Kushina guided them through the tunnels. This is not the first time she came here. So she isn't nervous. But Ren's nervousness was clearly showing on his face. He had seen nine tails in the anime many times. But that can't compare with meeting him face to face. The oppressive aura prevailing in the air and the huge amount of chakra they were sensing ahead of them, told Ren the fact that even if his chakra reserve is high, but compared to nine tails, it is just a fraction.
They soon reached a huge prison like gate. Inside two blood red eyes were glowing ominously. Though nine tails converged most of his aura, that didn't do anything to decrease his intimidating aura. Near the sealed gate, they can clearly feel the huge amount of chakra.
"Man, I thought my chakra reserve was somewhat large, but this is HUGE!"
Ren thought that nine tails atleast has half the chakra reserve of Ten Tails.
"Looks like Hagoromo took special care about nine tails."
Nine tails figure became clearer, when they got near. An enormous fox with nine swaying tails like snake with a height of more than 100m, bound by chains which were keeping him from any sudden movement. Ren knew that these were Uzumaki's Adamantine Sealing Chains. It can seal even tail beasts and suppress their powers. First hokage's wife Uzumaki Mito single handedly sealed nine tails within her body using these chains. After looking at nine tails bound by the chains, Ren decided to ask Kushina to free him. Nobody likes being bound all the time.
"Hello! Nine Tails or should I call you, Kurama."