What is the effective energy range in DOS and bandstructure plot ? How does decide effective energy range in DOS or PDOS and in bandstructure plot.

For example if I am doping any element in host compound then bands or PDOS of that element are coming near by valance band edge as well as inside the valance band and also in conduction band. How will decide dopant is making V.B or C.B

I have attached here fig. 1: PDOS and  fig. 2: Bandstructure of undoped fig. 3: doped system LaVO4:Eu (Eu dopant) which is showing half metal but I am interested how to analyze these plot in terms of which one is making V.B and which one is making C.B. These are trap states or band states.

In case of effective energy range in my case, I have taken -4 eV to +6 eV. How does decide this and according that how to analyze elemental contribution in PDOS ?