Note: The first Tundra mission itself requires lv30 and is only available in hard mode. There is no normal mode Tundra.
Level Cap Increase
You need to collect 90 objects that drop from monsters on Lilipa, Naberius and Amduscia (for a total of 270 objects, eep). They only drop from enemies between lv21 and 40. This will increase your level cap to 40.