Spring

Location
Spring is a Djinni that is automatically handed to you as you play through the game, being present on Piers as soon as he joins your party in the town of Kibombo somewhat early on in The Lost Age. Spring is one of three Djinn in The Lost Age - the others being Echo and another Mercury Djinni in Piers' possession, Shade - that is impossible not to obtain.

Description
When Set, it increases base HP by 11 and base PP by 5.

When Spring's battle effect is used, a targeted Adept on the player's side has their HP cured by an amount equal to 70% of their maximum HP. It is almost identical to the Mercury Djinni Fizz from the first game, only a little stronger.

Ability analysis
While appearing to be easily understandable and practical as a battle option, it is not very useful as an ability in practice because of the abundance of easier-to-use and more direct healing items and Psynergy available. And while it's technically one of the only effects available to the party that cures HP based on maximum HP meter - thus making it technically better over the course of the game as the Adepts gain more HP - the items and Psynergy become better and more practical as well. There will be cases where using it will not cure as much as a simple usage of a Psynergy from the Ply Psynergy series, and the fact it saves PP that would have been spent on Ply spells otherwise does not seem enough of an advantage to make up for it. Neither does the fact that Spring is technically superior by ten percentage points to the previous game's Mercury Djinni Fizz, which would return along with Isaac's party when they join Felix's party late in The Lost Age.

Name Origin
A spring is a small release of water from the Earth.