When you enter Southern Dragon Valley, there is nothing to be found. However, as hinted by the descriptions for both the Nannah Dragon you need to defeat to enter the valley, and the Dragon Meat it drops, there is a secret enemy here.
|Maegrik Dragon ×1||Event|| Dragon Meat ×3–30 (high chance)|
Brilliant Crystal ×1 (low chance)
| • Use Dragon Meat from inventory to summon Maegrik enemy
• May be more efficient to farm in lategame/post-game for Brilliant Crystals