Electrons gyrating around magnetic field lines emit electron cyclotron emission (ECE) ra- diation at the frequency Ωc = neB/(γm), where e is the elementary charge, B is the magnetic field amplitude, m is the electron rest mass, γ is the relativistic factor and n is the harmonic number [2]. In the presence of a magnetic field amplitude gradient, as in a tokamak, the ori- gin of emission is related to the frequency of the emission and a temperature profile can be reconstructed by scanning a range of frequencies, which is a common application of ECE di- agnostics. In certain scenarios, the plasma may contain a significant fraction of suprathermal particles whose energies exceed that of the thermal particles by several orders of magnitude, affecting both temperature measurements and profile reconstructions. Measuring ECE at var- ious frequencies along vertical lines of sight (VECE) [1] , along which the magnetic field B is constant, means that any variation in the observed radiation comes from a variation in the electron relativistic factor γ. On the other hand, reconstructing the 3D bounce-averaged guid- ing center electron distribution function from ECE measurements is an ill-conditioned problem and a more promising approach consists of constructing an equivalent synthetic ECE diagnostic providing simulations that can be directly compared to measurements. In this contribution, a new general synthetic ECE diagnostic that includes the effect of suprathermal electrons is constructed: the Yoda code. This code is able to calculate: i) the EC emission and (re)absorption based on any numerical electron distribution function calculated by any first-principle kinetic code (such as the 3-D bounce-averaged relativistic Fokker-Planck code Luke [4]) for an arbitrary line of sight simulated using the c3po [6] ray-tracing code (which also models the detection system); ii) the transport of EC radiated intensity along the propagation path. In this work, the Yoda code is validated for thermal plasmas against the ECE synthetic diagnostic spece [5], and two direct applications to TCV tokamak electron cyclotron current drive (ECCD) experiments are demonstrated with good agreement between the experimental vertical ECE measurements and synthetic intensity trends. This work has the potential to open new paths in the understanding of fast electron dynamics in tokamaks using synthetic ECE and synthetic HXRS [3] as constraints in first principle kinetic simulations. References [1] A. Tema Biwole et al. “The Vertical ECE of TCV”. submitted to review of scientific instruments. 2023. [2] M Bornatici et al. “Electron cyclotron emission and absorption in fusion plasmas”. In: Nuclear Fusion 23.9 (1983), p. 1153. [3] D. Choi et al. “Study of suprathermal electron dynamics during electron cyclotron cur- rent drive using hard x-ray measurements in the TCV tokamak”. In: Plasma Physics and Controlled Fusion 62.11 (2020), p. 115012. [4] J Decker and Y Peysson. DKE: A fast numerical solver for the 3D drift kinetic equation. EUR-CEA-FC-1736. Euratom-CEA, 2004. [5] D. Farina et al. “SPECE: a code for Electron Cyclotron Emission in tokamaks”. In: AIP Conference Proceedings. Vol. 988. 1. American Institute of Physics. 2008, pp. 128–131. [6] Y. Peysson, J. Decker, and L. Morini. “A versatile ray-tracing code for studying rf wave propagation in toroidal magnetized plasmas”. In: Plasma Physics and Controlled Fusion 54.4 (2012), p. 045003