Effector of the programmed cell death (PCD) activators rpr, grim and hid (PubMed:9740659). May play an apoptotic role in the germline as well as soma. Fadd interacts with Dredd to promote cleavage of Dredd and is necessary and sufficient for enhancing Dredd-induced apoptosis (PubMed:10934188). Plays a role in the innate immune response. Required for resistance to Gram-negative bacterial infection (PubMed:11269502). Diap2-mediated ubiquitination of Dredd is critical for processing of imd and rel and the subsequent expression of antimicrobial genes such as DptA (PubMed:22549468). 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 (PubMed:9740659). Interacts (via N-terminus) with Diap2; likely to bind Diap2 simultaneously with Fadd to form a trimeric complex (PubMed:10934188, PubMed:22549468). Constitutively expressed in fat bodies of larvae and adults. Expressed both maternally and zygotically. Embryos exhibit ubiquitous low level of expression until stage 11 and then expression becomes spatially and temporally restricted to areas of PCD. Polyubiquitinated by Diap2 following activation of the immune deficiency (Imd) pathway. Belongs to the peptidase C14A family.