When first encountered by Ryu, Jean is a large talking frog in a pond, who asks him to visit the witch Nimufu and have her undo the curse that she placed on him. When they return with the cure (a kiss from a young girl), Jean transforms back into his original form. His true form ironically is still that of a large frog, but is much more humanoid and bipedal than before.
Upon returning to his home of SimaFort, Jean is immediately arrested and thrown in jail. It is later uncovered that an imposter had infiltrated the castle during Jean's absence and seemingly convinced everyone that he is the real Jean. With the help of Jean's sister Petape, Ryu and the party manage to uncover the plot and expose the imposter, who turns out to be the demon Kuwadora. Jean is freed from prison and decides to accompany Ryu and the others on their journey.
Jean is incredibly optimistic and carefree, and also rather oblivious to the seriousness of situations, such as his cursed state and his potential execution at the hands of an imposter prince. He is known to frequently shirk any royal duties so that he can wander and be free, which causes no small amount of frustration for his sister. Despite this, Jean is very loyal and genuinely a good person, and is very popular among his subjects. Jean has an uncharacteristic ability to see the good in people, such as when he attempts to befriend the witch Nimufu.
Jean's field ability is Frog Transformation, where he transforms into a giant frog and hops around the world map. Jean can bypass ledges similar to Sten with this ability, and can also traverse shallow bodies of water. Random fights do not cease in this form.
In combat, Jean is considered to be less than average overall. He does possess good defense and a rather unique selection of spells. However, other characters can hit harder, others can act quicker and others have a better choice of spells overall. He is mainly useful for having the Hush spell and a high enough wisdom rating to make it work on bosses. Jean is a great mode of transportation for the early part of the game due to his field ability and learning the Warp spell at a relatively low level. Later in the game though, he quickly gets overshadowed by other party members. Jean's combat ability is Jab, which allows him to strike at all enemies on the screen for reduced damage.
Jean is able to join with the Shamans and can transform into a thinner, taller and more heroic-looking swashbuckler style frog character. This form grants him access to a deadly technique called Chop that can finish off monsters regardless of how large their HP total is; all Jean needs to do is use one turn to conserve power and by the next he executes Chop (though it can fail). Joining with the Shamans can also help to offset some of his lower stats, allowing him to last longer and cast magic more efficiently.
Amusingly, the name Jean introduces himself with, "Ekaru Hoppe de pe Tapeta", is actually his name in the Japanese game.
He speaks with a French accent in the English version of the game and nearly his entire dialogue is peppered with standard French words.
Jean can be seen as the comic relief character of the game with his storyline and overall attitude.
Jean's introduction story is a play on the old children's fairy tale, The Frog Prince.
Jean's quest for the Golden Fly in his story arc, is a reference to a similar quest in the original Breath of Fire, where the party has to capture a Golden Fly for some talking frogs to obtain their Frog Oil.