  Scattering amplitudes in Yang-Mills theory are known to exhibit kinematic
structures which hint to an underlying kinematic algebra that is dual to the
gauge group color algebra. This color-kinematics duality is still poorly
understood in terms of conventional Feynman rules, or from a Lagrangian
formalism. In this work, we present explicit Lagrangians whose Feynman rules
generate duality-satisfying tree-level BCJ numerators, to any multiplicity in
the next-to-MHV sector of pure Yang Mills theory. Our Lagrangians make use of
at most three pairs of auxiliary fields (2,1,0-forms) -- surprisingly few
compared to previous attempts of Lagrangians at low multiplicities. To restrict
the Lagrangian freedom it is necessary to make several non-trivial assumptions
regarding field content, kinetic terms, and interactions, which we discuss in
some detail. Future progress likely hinges on relaxing these assumptions.
