"Mother" would imply that the RSK Mk3 was derived from the Fixed Grip, which would imply that it came first. That is not really the case. While Benchmade had long considered making a fixed blade based on their successful Griptilian folder, my desire to make a fixed blade version of the RSK Mk1 and the sketch I provided http://www.equipped.org/pp/pic3007.htm served as a catalyst. The original thought was that, like the RSK Mk1 collaboration, that by them producing their "mass-produced" version and me being able to simply offer a different blade style, steel and finish using the same handle, the project would be more practical from a production standpoint and the cost lower overall. However, the more we worked on refining things and they got the detailed handle design and materials to where they wanted it for their marketing and pricing purposes, it no longer was satisfactory from my perspective. So, in the end we produced an entirely separate knife for the RSK Mk3. So, a better familial description would be that they are "siblings" with a common parentage.