Manda is the personal summon of Orochimaru, likely due to Orochimaru being the only one with enough chakra who has signed the snake contract who is still alive. He is the King of all of the Snakes, and the most powerful Snake that is possible to be summoned via ninjutsu.Â
Personality
Manda is very arrogant and demanding, even of those who sumon him. it is said that he eats those who summon him that he feels are unworthy or who show they are not powerful enough, showing that he is ruthless and cold hearted (even by Snake standards).  He also demands tribute of those who summon him in the form of sacrifices, preferably human or likely other intelligent animals. In the Sannin battle, he demanded one hundred human sacrifices to appease him for the trouble of answering the summons. Even Orochimaru showed fear of him when he was disabled, unable to use Ninjutsu due to his arms status. Kabuto was seen admitting that if Manda found out that even Orochimaru was incapable of using ninjutsu, it was likely he would turn on them and kill them.
Abilities
Manda has shown himself an incredible fighter, able to take on both Katsuyu and Gamabunta both at the same time. He is shown to be fast, accurate and extremely arrogant in battle, disabling his opponents using his immense strength and lithe form to crush them, also able to deliver deadly bites, with were also laced with poison. He is likely the most deadly of the three Sannin boss summons, though also the most trecherous. He is also able to create clones via shed skins to fool his opponents, and also possesses the ability to burrow underground at high speeds.
Status
Manda died in the battle between Uchiha Sasuke and Deidara when Sasuke summoned him to take an explosive blast that would have killed him. He was mesmerised by the eye power of Sasuke, who then jumped in Manda’s mouth and unsummoned Manda, riding back with him to the intelligent snakes place of residence, which is currently unknown. He then relied on Suigetsu to summon Manda back closeby, where he exited. Manda’s last words were used to curse Sasuke for his trechery which is ironic, yet fitting.