As he gazed at the medium-sized group of people, Arthur started inspecting every potential body he can possess. He can't just possess anyone then randomly use fire-related skills, it would be suspicious if he were to use a skill that the 'host' never used before and it'll obviously attract suspicions.
The closer the candidate to be possessed is to Elo Huo, the better as he would be able to influence the boy and get on with his plans without any hindrance.