In this paper we show how relativistic tensor dynamics and relativistic electrodynamics can be formulated in a bi-quaternion tensor language. The treatment is restricted to mathematical physics, known facts as the Lorentz Force Law and the Lagrange Equation are presented in a relatively new formalism. The goal is to fuse anti-symmetric tensor dynamics, as used for example in relativistic electrodynamics, and symmetric tensor dynamics, as used for example in introductions to general relativity, into one single formalism: a specific kind of biquaternion tensor calculus.