Thor is a true member of GREMLIN and one of its representative combat members. He is very casual, even when it comes to enemies. Despite being the specialist in war, Thor is not a person that gets turned on with bloodshed, and prefers to avoid unnecessary conflict that includes innocent people.
But true to his namesake, Thor does indeed enjoy combat, when there are no distractions, no fear of collateral damage on bystanders. He enjoys helping people but enjoys gaining strength as well. In fact, he cannot determine himself if he gains power to save people, or save people so he could gain power, an ambiguous state that he repeatedly thinking over.
Regardless, Thor is someone who is determined to follow his own path. He is a hard worker, who, despite being a normal magician, managed to climb up to the top of the ranks on his own without having a special power, and even able to contend against a Saint.