Fukasaku

and, better known as Ma and Pa are two Toad Elders from Myobokuzan that taught Jiraiya senjutsu in his youth. Because he is vastly younger than them, Jiraiya speaks quite respectfully to the Toad Sages, while they refer to him as "Jiraiya-chan" or "Kiddo", (Fukasaku starts calling Naruto "Naruto-chan" during his senjutsu training). They are apparently attendants to the Great Toad Sage.

Personality
Both toads are considered old and wise and are greatly respected by all who know them well enough. In reality, they constantly bicker over small things when they should focus on the bigger picture, such as the fact that a battle will cause them to miss dinner.

It would seem that only Fukasaku can remain serious in even the worst situation, while Shima will constantly find a way to bicker with Fukasaku. She, similarly, does not have enough respect for the Great Toad Sage, calling him senile for constantly forgetting everything.

Shima and Fukasaku both seem to like Naruto: Fukasaku meets Naruto first when he brings the news of Jiraiya's death to Konoha, he finds Naruto's nickname for Jiraiya ("Pervy Sage") to be both very fitting and very funny, but observes that Naruto, as he is, would not stand a chance against Pain and offers to take Naruto away to learn Senjutsu to become a Sage at Mount Myoboku. After (what was for Naruto) a confusing introduction to sensing natural energy and drawing it in to blend Sage Chakra, Fukasaku, (in light of Naruto's rapid progress,) believes that Naruto will surpass Jiraya in power.

Shima is very welcoming to Naruto when he first goes to Mount Myoboku to train, 'pulling out all the stops' at her and Fukasaku's home. Even though her cooking consists of stewed bugs, Naruto still eats it (but has difficulty keeping it down). During the Battle of Konoha, after Pain stabbed Fukasaku and pinned Naruto to the ground through his hands, Shima called to Naruto not to give up because both Jiraya and Fukasaku had given their lives because they believed in Naruto and if he gave up then she'd never forgive him--before Pain knocked her out to shut her up.

Though they constantly bicker, Shima is shown to be heartbroken when Fukasaku is killed by Pain.

Hunt for Itachi arc
Jiraiya summons Shima and Fukasaku during his fight with Pain to help him enter Sage Mode. In addition to sitting on his shoulders to provide him with natural energy, they give him advice and attack Pain when necessary. Their combined efforts are enough to combat three of Pain's bodies on equal terms. Shima and Fukasaku then create a genjutsu that allows them to kill the three bodies, but they are soon overwhelmed by the appearance of three more.

Knowing the battle is lost, Jiraiya has Shima take the Animal path he had captured back to Konoha. While she does that, Fukasaku accompanies him during his final confrontation with Pain. When he discovers Pain secret, he carves a message into Fukasaku's back and sends him away before dying of his injuries.

Senjutsu Training arc
Fukasaku informs Konoha and Naruto Uzumaki of Jiraiya's death, telling them what he can of Pain and allowing them to photograph the message on his back. Knowing that Naruto wants revenge and that he is currently ill-prepared for a battle with Pain, Fukasaku takes him to Myobokuzan to teach him senjutsu. While Naruto practices tuning in with nature, Fukasaku beats him (and his shadow clones) with a staff to keep him from taking in too much natural energy.

Naruto rapidly progresses through the training stages, earning praise from Fukasaku for so quickly catching up to Jiraiya. Once Naruto attains Sage Mode he teaches him Frog Kata. After Naruto masters the fighting style, Fukasaku begins the final step of trying to fuse with Naruto as he did with Jiraiya, something that proves impossible because of the demon fox sealed within Naruto. Worried that all his training will have gone to waste, Naruto tries to find a way to achieve Sage Mode without Fukasaku.

Invasion of Pain arc
While Naruto continues trying to find an alternative, Fukasaku is informed of Kosuke's death, indicating something is happening in Konoha. Shima, who is shopping near Konoha, also notices that something is wrong in the village. She summons Naruto, Fukasaku, Gamaken, Gamabunta, Gamakichi, and Gamahiro to Konoha's center moments after Pain destroys the village. As Naruto engages Pain, Shima and Fukasaku provide assistance, dealing with the Animal path's summons. They are amazed by his perfected Wind Release: Rasenshuriken, something he had not shown them during his training, but are again forced to deal with the Animal path.

Knowing that the Animal path must be gotten rid of, Shima coats the area in a dust cloud while Fukasaku throws Gamabunta at the path, giving Naruto an opportunity to finish it off. When the prolonged fighting causes him to exit Sage Mode, Fukasaku summons one of the shadow clones that was left behind in Myobokuzan. Because he could not have Shima and Fukasaku gather natural energy for him, Naruto decided to have his own shadow clones do it instead. Pain is soon left with only one body, and Shima and Fukasaku try once again to use a genjutsu to defeat it. Pain kills Fukasaku and knocks Shima away before they have a chance. Their bodies are later found and Shima, once healed, cries for Fukasaku. When Pain is defeated and subsequently chooses to revive everyone he has killed, Fukasaku is brought back to Shima's shock and suprise. Later, Shima and Fukasaku are both seen together, standing atop Gamakichi's head, watching from a distance as the population of the Konoha welcomed Naruto back from his confrontation with Nagato.

Abilities
In battle, Shima and Fukasaku are extremely formidable. Shima can extend a serpent-like creature from her stomach that can seek out the opponent, allowing Fukasaku to quickly strike with his tongue. Both are capable of exerting powerful gusts of wind, while Shima is able to breathe fire. Also, they seem to be very intelligent, as they quickly determined a weakness in the way Pain uses his Rinnegan.

The two toads are capable of using a very powerful genjutsu called Demonic Illusion: Toad Confrontation Singing. This ability cancels out Jiraiya's lack of aptitude for genjutsu, making their combination much stronger. However, this genjutsu takes time. Also, in order to use this technique, both Shima and Fukasaku must adjust their voices and harmonize with each other (something neither of them seems happy about doing). When finally applied, it attacks the opponent's sense of hearing and will completely paralyze the target(s) body. It gives Shima and Fukasaku a sore throat afterwards, meaning it can only be used once.

Shima and Fukasaku are able to use senjutsu. Senjutsu is a specialized field of jutsu that allows the user to sense and then gather the natural energy around a person and draw it inside them, blend it with their own chakra to create "Sage Chakra". This natural energy-empowered state grants the practitioner a high amount of a type of chakra that's stronger than other types of chakra. Other benefits include an unnaturally high level of raw strength, incredible speed, and huge resistance to physical attacks.

Trivia

 * Fukasaku is one of the characters in Naruto to experience death and be brought back to life. The others to have experienced this are Gaara, Kakashi Hatake, Shizune and the many victims of Pain's wrath on Konoha.