Three-dimensional Topological Insulators are bulk insulators with Z2 topological order that give rise to Dirac surface states. These states are well protected against weak perturbations that does not break time-reversal symmetry such as non-magnetic potential disorders. However recent studies have shown that non-magnetic point-like defects can introduce new in-gap states. We developed a numerical model to simulate point defects on a TI surface. We find that resonance state associated with the defects can hybridizes with the Dirac cone surface state and create kink-like feature in the band structure near the Dirac point. These resonance state are not Anderson localized even though they cluster around the defects sites. We discovered that these resonance states support diffusive transport in simulation and can be used to engineer the band structure of a TI since defect densities and chemical potential are controllable during sample growth. We also performed Dichroic and micro ARPES measurements to confirm the existence of these resonance states.