A composite fusion filament is disclosed that includes a polymer encasement and one or more mesogenic reinforcement bodies contained within the polymer encasement. The polymer encasement is comprised of a thermoplastic polymer, which has a melting temperature, and each of the one or more mesogenic reinforcement bodies is comprised of a thermotropic liquid crystal polymer, which has a clearing temperature. The melting temperature of the thermoplastic polymer included in the polymer encasement is less than the clearing temperature of the thermotropic liquid crystal polymer included in the one or more mesogenic reinforcement bodies. Additionally, the thermotropic liquid crystal polymer of each mesogenic reinforcement body has a plurality of organized crystalline fibrils that are aligned lengthwise along a longitudinal axis of the polymer encasement. A method of using the composite fusion filament to form a bond with a substrate that includes a thermoplastic polymer is also disclosed.