Clue: Box for an emperor, Giza by the sound of it — more than one of those? (10)
Answer: SARCOPHAGI
Explanation: Definition: more than one of those?
Sounds (approximately) like TSAR ('emperor') COFFER ('box') GUY (geezer, 'Giza by the sound of it'). In the definition 'those' refers back to 'box'.