Question

And on the pedestal these words appear my name is ozymandias king of kings look upon my work ye myghty and despair nothing beside remains.What is the irony in these line

Answer 1

Ozymandias was very mighty, arrogant, and was blind in power. He refers to himself as 'King of Kings' because he was so boastful and proud that he considered himself to be above all. This reveals that he was certainly confident to his might and extraordinary power.
And he referring to any warrior or king who thinks he is stronger than Ozymandias, when he speaks of 'ye mighty'. He thinks that they would despair when they see his might and his works because they cannot match him.

Answer 2

Ozymandias,an arrogant and a powerful ruler well known for his boastful nature claims himself to be the king of kings and in a boastful manner suggests the mighty to look at his extraordinary work but the irony is that the statue got wrecked,nothing else remains expect those shattered pieces in a lonely desert.
.....Hope it helps u...