Surface defects provide a powerful window into strongly coupled quantum field theories. In this talk, I will present closed-form results for how surface defects contribute to the energy and entropy in six-dimensional theories. First, the defect contribution to twisted Rényi entropy takes a remarkably simple form: it is linear in 1/n where n is Rényi index, and controlled entirely by the defect Weyl-anomaly coefficients. I will also describe an equally compact expression for the defect contribution to the supersymmetric Casimir energy, which reduces to the known formula in the chiral-algebra limit. These results highlight a precise bridge between defect conformal anomalies and defect observables relevant to entanglement and Casimir energy.