<p>The propagation of Electromagnetic Ion Cyclotron (EMIC) waves is strongly influenced by deviations from ideal plasma conditions that are commonly present in near-Earth space environments. In This study investigates how a parallel electric field and non-Maxwellian ion populations, represented by the Kappa distribution function, affect EMIC wave behavior in a multi-ion magnetized plasma consisting of H⁺, He⁺, and O⁺ ions. The analysis is carried out for parallel wave propagation in a homogeneous, low-beta plasma, representative of the Earth’s auroral acceleration region. Using a kinetic, particle-based approach, we examine the modification of the dispersion relation and quantify the resulting changes in resonant energy, growth rate, and growth length of EMIC waves. The presence of a parallel electric field alters the particle–wave resonance condition, leading to noticeable shifts in resonant energies and a corresponding change in wave amplification and damping. Moreover, the inclusion of a Kappa distribution highlights the important role of suprathermal ions, which significantly enhance or suppress EMIC wave growth compared to the Maxwellian case. These results emphasize the combined influence of electric fields and non-thermal particle populations on EMIC wave dynamics and provide improved insight into waveparticle interactions, energy transport, and particle acceleration processes in space plasmas.</p>