An airfoil assembly (20A, 20B) for use in an airfoil cascade, the airfoil assembly (20A, 20B) comprising: a first airfoil; and a second airfoil, wherein each of the first and second airfoils (20A,20B) comprises: an airfoil working portion; an endwall adjoining an end of the airfoil working portion, the endwall having a leading edge, a trailing edge, a first mateface, and a second mateface, wherein the first and second matefaces (26, 28) are arranged opposite one another, and the leading edge, trailing edge, and first and second matefaces (26, 28) collectively define a perimeter of the endwall; a forward zone defined by the endwall that extends to the leading edge, wherein the first and second matefaces (26, 28) are each oriented at an angle α II relative to a radial direction in the forward zone; an aft zone defined by the endwall that extends to the trailing edge, wherein the first and second matefaces (26, 28) are each oriented at an angle α I relative to a radial direction in the aft zone, and wherein the angles α I and α II are not equal; and a middle zone defined by the endwall in between the forward and aft zones (100, 102), wherein the first and second matefaces (26, 28) transition between the angle α II and the angle α I in the middle zone; wherein the first and second airfoils (20A, 20B) are arranged such that the first mateface of the first airfoil adjoins the second mateface of the second airfoil with a gap between the adjoining matefaces (26, 28). a first airfoil; and a second airfoil, wherein each of the first and second airfoils (20A,20B) comprises: an airfoil working portion; an endwall adjoining an end of the airfoil working portion, the endwall having a leading edge, a trailing edge, a first mateface, and a second mateface, wherein the first and second matefaces (26, 28) are arranged opposite one another, and the leading edge, trailing edge, and first and second matefaces (26, 28) collectively define a perimeter of the endwall; a forward zone defined by the endwall that extends to the leading edge, wherein the first and second matefaces (26, 28) are each oriented at an angle α II relative to a radial direction in the forward zone; an aft zone defined by the endwall that extends to the trailing edge, wherein the first and second matefaces (26, 28) are each oriented at an angle α I relative to a radial direction in the aft zone, and wherein the angles α I and α II are not equal; and a middle zone defined by the endwall in between the forward and aft zones (100, 102), wherein the first and second matefaces (26, 28) transition between the angle α II and the angle α I in the middle zone; wherein the first and second airfoils (20A, 20B) are arranged such that the first mateface of the first airfoil adjoins the second mateface of the second airfoil with a gap between the adjoining matefaces (26, 28). an airfoil working portion; an endwall adjoining an end of the airfoil working portion, the endwall having a leading edge, a trailing edge, a first mateface, and a second mateface, wherein the first and second matefaces (26, 28) are arranged opposite one another, and the leading edge, trailing edge, and first and second matefaces (26, 28) collectively define a perimeter of the endwall; a forward zone defined by the endwall that extends to the leading edge, wherein the first and second matefaces (26, 28) are each oriented at an angle α II relative to a radial direction in the forward zone; an aft zone defined by the endwall that extends to the trailing edge, wherein the first and second matefaces (26, 28) are each oriented at an angle α I relative to a radial direction in the aft zone, and wherein the angles α I and α II are not equal; and a middle zone defined by the endwall in between the forward and aft zones (100, 102), wherein the first and second matefaces (26, 28) transition between the angle α II and the angle α I in the middle zone; wherein the first and second airfoils (20A, 20B) are arranged such that the first mateface of the first airfoil adjoins the second mateface of the second airfoil with a gap between the adjoining matefaces (26, 28).