Effector of the programmed cell death (PCD) activators rpr, grim and W. May play an apoptotic role in the germline as well as soma. Role in immune response, required to resist Gram-negative bacterial infections by regulating DptA. Fadd interacts with Dredd, Fadd promotes cleavage of Dredd and is necessary and sufficient for enhancing Dredd-induced apoptosis. Strict requirement for Asp at position P1 and has a preferred cleavage sequence of (Leu/Asp/Val)-Glu-Thr-Asp-|-(Gly/Ser/Ala). Heterotetramer that consists of two anti-parallel arranged heterodimers, each one formed by a 15 kDa (caspase-8 subunit p15) and a 10 kDa (caspase-8 subunit p10) subunit. Interacts with the N-terminus of Fadd (By similarity). Belongs to the peptidase C14A family.