surname Zang
Depicts a weapon (戈) slashing an eye (臣). In ancient China, captured prisoners were blinded with weapons making them into slaves. 爿 was later added as a sound component. Based on the original meaning, "slave; servant". The current meaning "good" is a phonetic loan.
《說文》：“臧，善也。从臣，戕聲。，籀文。”
slave; servant