Jiraiya - Page 16

You first see him peeping in the women bathing place to "collect material". Naruto then gave him his nickname "ero-sennin" meaning "perverted hermit". Although he is kinda stupid and funny, he truly is a master ninja. He teaches Naruto to control his 2 chakras and to summon toads. He also tought Naruto the Rasengan.

As such, Jiraiya's fighting techniques are mostly defensive, His "Underworld Swamp" immobilizes a large amount of ninja's in a marsh, and his "Underworld Spines" defend him from any physical attack. He mostly relies on his summoning frogs to aid him, though he rarely summons Gamabunta.

There might be a good reason why he specializes in defensive techniques, and that is because he is a complete and utter pervert, who writes a series of books known as Icha Icha Paradise, a book Kakashi himself adores. As such, he has grown so adept at peeping he is very rarely caught.