Tang Jia San Shao
I like the fact that in DD4 they were able to add more way to have action DD3 had to have a lot of tournaments since Soul beasts were going extinct and they couldn't do fights where they hunt for Soul rings, but DD4 is making it up with the simulation world and space battles along with being more tactical.
The tactics and using the different roles of soul masters in combat is always my favorite thing about every Doulou Dalu, in the beginning of the story atleast. I say that because once we get to the middle part of the story and then all the way through to the end, all of that stuff gets thrown out and replaced by combat power. Meaning tactics and your soul master role dont matter if you have a weaker combat power than the person you are facing. At least that is the way it was in DD1 and DD3, I have not fully finished DD2 so I am not positive if it is the same in DD2.