The Ice and Fire Yin Yang Well is present in the Sunset Forest.
The Well is under the control of Tang Sect in SL3 and artifical wells were created on Forest Luo Planet and other places in SL4.
The hot spring isn't large, it is however split into two parts. In the oval pool, the waters of the hot spring is separately colored milky white and vermilion. Even more bizarre, even though they were in the same pool they remained clearly separated, not encroaching on each other and constantly keeping to their own sides.
It is said to be one of the three great treasure bowls, an extremely rare and valuable natural environment.
Ordinary plants are basically unable to grow in this environment since they cannot adapt to the special atmosphere, but certain valuable plants can nevertheless be cultured. The time required for cultivation of rare plants would be reduced tenfold.
The Ice and Fire Yin Yang Well isn't just for growing things. At the same time it had extremely unusual effects on the human body. If humans or maybe animals stayed at the side of the Ice and Fire Yin Yang Well, then in a very short time their bodies would be attacked by two kinds of extremely potent Heavenly spiritual influences. If they didn’t leave fast enough, their bodies were bound to burst and die.
The Dragon God had fallen in the Divine Realm, and the Nine Great Dragon Lords each had their own turn of fortunes in life. Among them, the Water Dragon King and the Fire Dragon King had fallen at the same time on this very piece of land. Their bodies were buried thousands of feet under the Icefire Polarized Eyes. In fact, that’s how the Icefire Polarized Eyes came about. Their essences nourished everything there.
Tang San used the herbs at the well to created Yama's Invitation and to temper his body and to improve his purple demon eyes. He took some of the herbs with him and gave them to the other Shrek Seven Monsters and Yu Xiaogang.