首先,这不是一个完整的句子,而是含有定语从句的名词短语。这个短语中:a creature作短语主体;who loved…screams整体作creature的定语从句,这其中who指代creature作从句主语;loved作从句谓语,(more than anything else作状语 ),后接不定式短语to spill their blood and laugh at their sufferings and their screams作loved的宾语,而中间的with joy作laugh的方式状语。