First go to Lan Chow near the warehouse coordinate (60.61around) to find a NPC called Mu Rong Hua. There, you will be able to obtain a pet quest from her.

Then, go to outside Lan Chow, near the top left hand side of the map (71.401 around) to find the Balla egg.

After finding the egg, go back to Lan Chow city and talk to Mu Rong Hua. She will tell you that in order to hatch the balla egg, you need to obtain these following items:

Big Balla's basket x1
Monster flower's soil x5
Big snail's extract x5

After gathering the above materials, go back to Mu Rong Hua and give the materials to her.Talk to Mu Rong Hua again and WALA! You have just obtained a balla as your pet!!!

Pet – How to obtain Progeny of Rei

Notice: Level 40+ is required to use this pet

First go to Lan Chow near the warehouse coordinate (60.61around) to find a NPC called Mu Rong Hua. There, you will be able to obtain a pet quest from her.

Now you must go to the entrance of Mo Go Cave to find the Corrupted Progeny of Rei located on (around 235,468) and talk to him.

Then, you have to kill flying columns in order to get the quest items.

After getting the required quest items, go back to the Corrupted Progeny of Rei and talk to him. And then you need to kill Progeny of Rei to get ten wings, kill Red Scorpions to get five rain cloud bottles,  kill museum thief to get five lightening bottles and finally kill Mo Go Spirit to get one bell of summoning.

After getting all these quest items, go back to Lan Chow and talk to Mu Rong Hua. She will ask you to find a box in Hua Chin pool.

The box is located towards the bottom left of the map (around 89.125). It is recommended that you maximize your map for easier finding.

After obtaining the box, go back to Mu Rong Hua and get your reward ---the Progeny of Rei!!!