It had been seven years since Tobi had passed away from his injuries. The first year had been very difficult for Zetsu, and if he didn't have Kisame there to take care of him, he would have killed himself.
Shortly after Tobi's death, the Akatsuki had begun dying off. Sasori was the first to go, followed by Hidan and Kakuzu. Neither Kisame nor Zetsu had expected Hidan and Kakuzu to fall, and Deidara died shortly after, attempting to kill Itachi's brother, Sasuke. Sasuke had won and moved on to kill Itachi next.
After Itachi died, Kisame and Zetsu began making plans to leave the Akatsuki, and that was when they had found out about a secret that Pein had fought desperately to keep from Zetsu. Tobi was raped and murdered because of the real leader of the Akatsuki, Madara. Madara had grown sick of the time Zetsu was wasting with Tobi when he could've been out training and doing his job, and he had broken out a criminal in order to kill Tobi off once they learned Zetsu and Kisame had disobeyed the order he gave Pein to give to them. How they had found out that Tobi had been hidden, neither Kisame nor Zetsu ever did find out.
Zetsu, not even aware there was someone else pulling the strings, had grown bitter and hateful, but thankfully, Kisame was there. That was about the time he and Kisame gotten together officially. Zetsu, although not yet ready to give all of himself to Kisame, allowed Kisame to kiss him and caress his body whenever he pleased.
It was when Pein and Konan died next just a year later that Kisame and Zetsu were ready to leave for good. Neither of them had any attachments left to the Akatsuki, and it was only Madara and themselves left anyway, now. In the attempt to escape Zetsu had been severely injured, but Kisame had protected Zetsu, getting him away from Madara and to safety.
They both had been rather shaken by Madara's sudden appearance and they both hated him for how he had treated Pein and the rest of the Akatsuki, and especially for Tobi's untimely death, and they both wanted to see Madara fall the way their own comrades did.
They travelled slowly to Konoha after Zetsu had healed enough to travel again, fully prepared to be killed in the attempt to use them to bring Madara down. As it happened, Tsunade had listened to their tales and made her decision; due to their honesty and willingness to turn against their own leader, she had allowed them to roam Konohagakure with their chakra sealed and ANBU watching their every move for a while until she trusted them not to cause any trouble.
They had been given their own home together in the village, their chakra unsealed, and after just a few months they heard that Madara had been killed off by Konoha and Sasuke had been brought back to his own village.
Kisame and Zetsu had lived in peace for a year with Tsunade making Zetsu anti-depressant medication, and once Zetsu was used to them, he had allowed Kisame to take him for the first time in their relationship.
It was only a few months later that Kisame had travelled back to the abandoned Akatsuki hideout with some ANBU accompanying him, gathering what photos and personal items he could recover of the other members, and placing Tobi's old belongings in several bags to bring back for Zetsu. The ANBU helped him return with all of this, and when he showed Zetsu, he had been so grateful he allowed Kisame to make love to him once again. Life had gotten better for the both of them, and they hoped it would stay like this forever.
It was on Kisame's birthday that Zetsu told Kisame something he had been dying to hear for all these years. They were sitting in the kitchen, eating the cake by themselves, quietly enjoying the others' presence.
"Kisame," Zetsu began, smiling happily - a true smile, "we love you."
Kisame smiled brightly, putting his cake down and leaning across the table to kiss Zetsu passionately. Zetsu smiled into the kiss, submitting easily, tugging on Kisame's hair gently.
"Where will we do it, tonight?" Zetsu asked simultaneously, blushing at the mere thought of making love.
Kisame smirked. "My pick, is it? Let's do it on the couch tonight."
Zetsu smiled happily, wrapping his arms around Kisame and allowing the older male to pick him up and carry him bridal style into the living room. Kisame gently laid Zetsu on the couch, climbing on top of him and grabbing the smaller man's cheeks with both hands, bringing their faces together and kissing him with all his love.
There was a lemon here. Please go to my adultfanfiction account to read it.