Fraus believed that he needed Cold, Heat and Poison resistance for a simple reason. These three elements are most used damaging things, he was poisoned by Genesis, it took him too much time to understand that he is poisoned in some sort of a hallucination. Which is a thing that he did not wanted to feel and have some sort experience again.
When it comes to Cold and Heat Resistance, he wanted it because of environmental damages can be done to his body. Fraus believed that he will encounter and reach the places where the air and environment is too cold or too hot, he did not wanted to spawn into some place and die instantly because of air is too cold for his natural body to resist or too hot that he burn to death instantly.
