Dragon Quest IX: Sentinels of the Starry Skies/Level Grinding

Though level grinding has no necessity for most of the story of the game, though there are some instances where it is necessary (primarily the last few boss battles), it means everything in the post-game, whether you're grinding through grottoes or reaching the max level of your vocation so you can revocate.

The Metal Slime Factor
When it comes down to it, most of the monsters that you come across throughout the main story simply don't cut it when it comes to experience. They certainly provide enough for you to make it through the majority of the story, but beyond that, they're useless. Here a key group of monsters come in: metal slimes. The experience that these slimes dish out range from 4096 (Metal Slime) to 240,000 (Platinum King Jewel). These slimes are incredibly rare and elusive, only being found in certain areas. These areas are as follows:


 * The Quarantomb - Metal Slimes
 * The Bad Cave - Metal Medleys
 * The Bowhole - Liquid Metal Slimes
 * Angel Falls highground - Metal Slimes, Metal Medleys, Liquid Metal Slimes
 * The Tower of Nod - Metal King Slimes (Note: they cannot be found roaming on they're own)
 * Grottoes - Liquid Metal Slimes, Metal King Slimes, Platinum King Jewels

Because of they're rarity, they only spawn every now and then, so it takes time and patience when hunting metal slimes, and maybe a little luck. You're easiest bet would be at either the Bowhole or the highground of Angels Falls (though higher-level grottoes are good sources as well). At the Bowhole the easiest thing to do is to camp out near a spawn point. To do this, head to the stairs that bring you down to the lowest level of the Bowhole. Head into the corner to the right of them, and you get a great view of the spawn point at the top of the steps leading up to the bridge. Now to sit and wait for an LMS to spawn. Once one spawns, you need to be careful on your approach, or it will see you and run and disappear. As for the highgrounds of Angel Falls, you can find both Metal Slimes and Liquid Metal Slimes roaming around, with Metal Medleys occasionally accompanying both in battle. Liquid Metal Slimes may seem to be more rare here than at the Bowhole, but there is a huge benefit. Often, Liquid Metal Slimes show with other Liquid Metal Slimes on the battlefield, meaning an increased likelihood of nailing one.