Prometheus kicked off the action of “What We Leave Behind” by using the information handed over to him by Evelyn to target Curtis.
Back in his first year of vigilantism, Oliver discovered Claybourne Pharmaceuticals when TB broke out in a struggling area of Star(ling) City, and he ultimately learned that Claybourne had deliberately released the bacteria as a bioweapon.
Since Claybourne’s name was on his list and was clearly a pretty bad guy, Oliver went to pay him a visit, and Claybourne ended up dead, leaving his illegitimate son to spend the next four years marinating on his anger at the Hood who killed his father.
He hit Curtis with a throwing star that turned out to be laced with a drug called dycloseral, which was first put into production years ago by Justin Claybourne of Claybourne Pharmaceuticals as a very pricy way to battle tuberculosis.