Ipsaeng is not in the ranks of the main role, but he has an important role. He really likes to cheat and is cunning, making us annoyed because he always brings our main lead (Eunseom) into trouble and danger. But he was also the one who taught Eunseom new things, opening his mind to seeing reality and the cruel world.
And because of his 'lie', Eunseom can become Inaishingi, the leader of the Ago Tribe.