Composite reinforcer (R-2) capable of adhering directly to a diene rubber matrix, which can be used as reinforcing element for a tire, having one or more reinforcing thread(s) (20); a first layer (21) of a thermoplastic polymer, the glass transition temperature of which is positive covering individually the thread or several threads; a second layer (22) of a composition having a poly(p-phenylene ether) (“PPE”) and a functionalized unsaturated thermoplastic styrene (“TPS”) elastomer, the glass transition temperature of which is negative, the elastomer bearing functional groups selected from epoxide, carboxyl, acid anhydride and acid ester groups, in particular an epoxidized SBS elastomer, covering the first layer (21). Process for manufacturing a composite reinforcer and rubber article or semi-finished product, especially a tire, incorporating such a composite reinforcer.