Provided herein are variant human IL18 proteins including proteins and constructs including such. Various variant IL18 proteins with modifications to reduce heterogeneity and/or reduce affinity/potency and/or improve stability and/or improve production yield are also described. Also provided are IL18-Fc fusion proteins that include an empty-Fc domain and an IL18 protein connected to another Fc domain. Also provided herein are IL18Fc fusion proteins that bind CD3 and a tumor target antigen.