A multi-wall blade comprising a trailing edge cooling system, the trailing edge cooling system comprising: a coolant feed; a coolant collection passage; a plurality of sets of outward legs configured to extend axially toward a trailing edge of the multi-wall blade and fluidly coupled to the coolant feed; a plurality of sets of return legs configured to extend axially toward a leading edge of the multi-wall blade and fluidly coupled to the coolant collection passage; and a connecting system for fluidly coupling the sets of outward legs and the sets of return legs; wherein the sets of outward legs are radially offset from the sets of return legs along a radial axis of the multi-wall blade, wherein the coolant feed is fluidly coupled to a plurality of sets of outward legs, and wherein the coolant collection passage is fluidly coupled to a plurality of sets of return legs; wherein each of the sets (160,162) of outward and return legs (134, 138) comprises at least two radially spaced legs (134, 138); wherein the sets (160,162) of outward and return legs (134, 138) are radially spaced in an alternating sequence along at least a portion of a radial length of the trailing edge; and wherein a first outward leg in a given set of outward legs is fluidly coupled by the connecting system to a return leg in an adjacent set of return legs, the return leg in said adjacent set of return legs being radially adjacent to the first outward leg, and wherein a second outward leg in the given set of outward legs is fluidly coupled by the connecting system to a return leg in another adjacent set of return legs, the return leg in said another adjacent set of return legs being radially adjacent to the second outward leg. a coolant feed; a coolant collection passage; a plurality of sets of outward legs configured to extend axially toward a trailing edge of the multi-wall blade and fluidly coupled to the coolant feed; a plurality of sets of return legs configured to extend axially toward a leading edge of the multi-wall blade and fluidly coupled to the coolant collection passage; and a connecting system for fluidly coupling the sets of outward legs and the sets of return legs; wherein the sets of outward legs are radially offset from the sets of return legs along a radial axis of the multi-wall blade, wherein the coolant feed is fluidly coupled to a plurality of sets of outward legs, and wherein the coolant collection passage is fluidly coupled to a plurality of sets of return legs; wherein each of the sets (160,162) of outward and return legs (134, 138) comprises at least two radially spaced legs (134, 138); wherein the sets (160,162) of outward and return legs (134, 138) are radially spaced in an alternating sequence along at least a portion of a radial length of the trailing edge; and wherein a first outward leg in a given set of outward legs is fluidly coupled by the connecting system to a return leg in an adjacent set of return legs, the return leg in said adjacent set of return legs being radially adjacent to the first outward leg, and wherein a second outward leg in the given set of outward legs is fluidly coupled by the connecting system to a return leg in another adjacent set of return legs, the return leg in said another adjacent set of return legs being radially adjacent to the second outward leg.