Steam

Location
Steam is located in the interior portion of the Aqua Rock dungeon, placed at the end of one stretch below a moai statue that spouts flowing water that prevents you from running up to reach it. You need to acquire the dungeon's Parch Psynergy first. Then climb up the right ladder and go up until you're just to the right of the top of the moai statue, and cast Parch on it. The flowing water will disappear. Climb down and walk up to Steam's position and battle it in order to earn it.

As an opponent
Statistically, Steam has 620 HP, 56 PP, 192 Attack, 54 Defense, 159 Agility, and 19Luck. Like all other Mercury Djinn that are fought, in terms of resistance, it has a Mercury Resistance rating of 193, Venus and Jupiter Resistance ratings of 100 each, and a Mars Resistance rating of 25, and in regards to its abilities it uses its available Mercury-based attacks with a Mercury power rating of 125.

Steam can use the following battle commands:
 * Glacier: Used 53 out of 256 times, this is a Psynergy spell that causes a large amount of ice shards to drop onto the party, dealing a Mercury-based attack with a power rating of 100 and a range of 3. This ability consumes 15 of its user's PP.
 * Hail Prism: Used 47 out of 256 times, this is a Psynergy spell that causes four large ice spheres to slam into the party of Adepts and shatter in quick succession, dealing a Mercury-based attack with a power rating of 90 and a range of 5. It consumes 16 of its user's PP.
 * Supercool: Used 41 out of 256 times, this is a Psynergy spell that summons a moderately large group of icy spikes out from the ground at the opposition, dealing a Mercury-based attack with a power rating of 80 and a range of 5. This ability consumes 14 of its user's PP.
 * Ice Horn: Used 35 out of 256 times, this is a Psynergy spell that shoots a mass of ice spikes down onto multiple Adepts, dealing a Mercury-based attack with a power rating of 70 and a range of 3. This ability consumes 11 of its user's PP.
 * Froth Sphere: Used 29 out of 256 times, this is a Psynergy spell that projects a moderately large array of watery spheres that arc into the party, dealing a Mercury-based attack with a power rating of 65 and a range of 5. This ability consumes 12 of its user's PP.
 * Attack: Used 28 out of 256 times, this is this monster's standard physical attack, but for this monster it is counted as a Mercury-based attack rather than a non-elemental attack.
 * Flee: Used 23 out of 256 times, this enemy has the ability to attempt to Flee the battle, thereby ending the battle if successful without rewarding you with the associated EXP, Coins, and the Djinni itself.

When felled, Steam yields 571 EXP and 457 coins and the Steam Djinni is added to your party's Djinn collection. If you fell it with an offensive Mars Djinni like Char, its rewards increase to 742 EXP and 594 Coins.

Description
When Set, it increases base HP by 10 and base Attack by 5.

When Steam's battle effect is used, all currently active and alive Adepts get buffed with an additional 40 resistance points to all their resistances. This is twice as strong as the effect of the Resist Psynergy. This is contrary to the game’s description of the Djinni’s effect as increasing “all allies’ Elemental strength.” The Jupiter Djinni Breeze from Golden Sun has the exact same effect.

Ability Analysis
Up until Isaac's party joins late in The Lost Age, Steam is the one Djinni that is Resist doubled in effectiveness, and when they do join the Jupiter Djinni Breeze they bring with them is a duplicate of this effect. Despite Resist being a Psynergy that starts becoming available for various Adepts at level 22, which is about the level various players are at or above when they get this Djinni in the first place, this can be a very valuable measure to lower the damage of boss enemies' elemental assaults toward you from when it is collected all the way up to the endgame. When Sheba is in her mono-elemental class series, the Wind Seer class series, she will learn Resist at 22, but unleashing Steam in battle should almost always be considered a superior option (even though it will likely come from Piers, a damage-dealing Mercury Adept) because it is a twice-as-strong effect that does not even detract from his PP-meter, and the fact his Djinni will be then put On Standby may better let him perform a Mercury summon the next turn. Note that resistance-buffing effects like these stack with each other up until all Adepts have +80 resistance rating modifiers.

Name Origin
Steam is what you get when you boil water.