Al-haitham has worshipped Their Grace for as long as he can remember. He's always sceptical about the imposter the moment they had entered Teyvat. When it turned out that the imposter was Their Grace he was one of the first people to try and search for them. Al-haitham also reprimanded the three Archons and Nations for not seeing the truth. Their grace will be brought back by him. He will be their saviour....Al-haitham is just obsessed with the thought of them....