Designers are constantly looking for ways and means to ensure safety of nuclear reactors. The challenge of Helium embrittlement in nickel-based alloys are currently unexplored in the nuclear industry. Helium bubbles have a detrimental effect on the mechanical properties of nickel. Despite numerous experimental and theoretical studies, the exact mechanism governing the helium induced embrittlement is not properly explored. In the present work, effect of various configurations of helium on mechanical properties of nickel crystal have been investigated using molecular dynamics simulations. The effect of different orientation of crack plane in conjunction with loading direction in a FCC crystal of Ni was scrutinized along with embedded helium bubble. Deformation was primarily found to happen by stair rod and Shockley type dislocation in two of the orientations, while, Lomer Cottrell locks and twinning are responsible for the deformation in third orientation. Helium bubble deteriorates the strength of single crystal of Ni containing an embedded crack. The results indicate that orientation of the crystal along with modulation of helium clusters is an implicit means to understand various defects in the crystal of Nickel.