I own nothing of Naruto, and make no profit from this.
Warning: Um, spoilers up until who Sasori's spy is revealed to be.
Author's Note: Partially dedicated to Eithne. I guess. Even though I probably butchered her beloved thoroughly. And although I stole her title idea. (Sorry, I loves you!! D: )
Sasori wasn't as bad as Kakuzu when it came to partners in Akatsuki. But he had had his fair share of them. After Orochimaru left and was replaced by Deidara, Sasori had decided that he didn't like partners. They were annoying, tended to die easily, untrustworthy, naïve in the ways of the world, and still annoying. Orochimaru had been decent, and the two got along well enough; they both had their own, strange obsessions with immortality. They often discussed it on long, tedious missions.
Deidara was loud, obnoxious, a pyromaniac, an 'artist', and nothing like Orochimaru. Orochimaru had been strong, quiet, and more importantly, not afraid to get his hands bloody. He had been vain, however, and Sasori suspected there was more than one reason in the Snake Sannin's head for joining Akatsuki (namely the most recent addition, a certain stoic Sharingan user). Deidara was interested in no one but himself and his partner, except as enemies or targets.
They were both so different, and their memories in Sasori's head clashed. But, even if the puppet master secretly preferred Deidara (sometimes) to (that bastard betrayer) Orochimaru, he had come to a single conclusion about partners.
They were an absolute waste of time.
So Sasori started recruiting many, many more subordinates and spies. They were more valuable, ultimately, and he didn't have to spend much time with any of them. Just a few jutsus, and voila; any ninja he chose was instantly loyal to him. Much better than having an eternally cheerful explosives expert following him around.
Oh, sure, many of them died in missions. Many of them were worthless. But Sasori could only tinker with puppets so much, and ended up recruiting many subordinates. There were a couple he came to value highly, however. One of them, a jounin from his native village of Suna named Yura, had been priceless with some of his informational tidbits. Another jounin in Kiri did the same, but Sasori couldn't help but feel more interested in the desert than the mists. It was his upbringing, his nature.
But, there was another spy that quickly rose in the mental ranks of Sasori's mind. He was a mere boy, but oh, the potential he possessed. A genin (although only by technicalities, he was sure to be around a high-level chuunin by now) from Konoha. The puppet master had subtly placed him into the Leaf village after what looked like the mysterious death of all of his family, and the boy had been loyal to him ever since.
He was already a fair medic nin, even in his young age, and was very possibly a genius in medical ninjutsu. (Still too early to tell, Sasori thought sadly.) He had supplied vast amounts of Konoha information, and the puppet master was considering having him become a key spy in his web of information.
Orochimaru had left. He still had his ring. He was powerful enough to be considered a threat. He needed to be kept tabs on…and before he even realized it, Sasori had had Kabuto inserted into the snake's ranks. And in those ranks he quickly rose. Until the boy was Orochimaru's right-hand shinobi. The medic nin was invaluable at that point.
Information from Konoha, and updates on Orochimaru's movements. Perfect.
But there was a sneaking suspicion…some unknown emotion was always there during their few-and-far-between meetings. Sasori wasn't sure that he completely trusted Kabuto. He knew for a fact that the boy was a master of controlling his emotions, body and facial expressions. More likely than not, Orochimaru had done something; Sasori remembered him as being rather paranoid in making allies.
When he met with Kabuto, he missed his partner.
When he was with Deidara, he missed his spies.
Sasori never was a happy person.