One might be wondering, how could Rean survive inside the Quasar, something even the Divinity Realm Expers didn't dare to get close to? Well, the main reason was definitely his Light Element.
It doesn't mean the Quasar is made of Light Element. It is mostly just energy, but above all, that energy was toxic to one's body. So, the closer you got, the harder it was to fend it off... except to Rean, who could simply use his Purification Skill to get rid of all the radiation poisoning in his body before it could affect his cells and DNA.
As for the unbelievably high temperature, that was actually easier to deal with. Rean was the epitome of Yang Energy, and he could control it around himself to fend off or resist the heat. Of course, it was still a challenging task to accomplish. Fortunately, Rean also had his Celestial Body, which was even more resistant than when he used the Starlight Body Cultivation Technique.