The protagonist is named Chiyang Shenguang, a native of World 555.
After he was born, his family endured natural and man-made disasters, including fires, floods, gas leaks, and earthquakes. In the end, he was the only one left alive.
Later, Hanagata brought him to Ryusei School, where he became one of its students. After being rescued, his classmates and Hanagata treated him well, so he grew into a kind person who cared for and looked after others. That's why they called him the Warm Sun.
At a class reunion, he awakened as a Cockroach Orphnoch, with incredible vitality and high resistance to both physical and magical attacks.
Since he rarely went after humans, and only targeted the most despicable people to boost his record, he never became a member of the Lucky Clover.
The protagonist still has a human heart. Later, he chooses to take up the Kaixa Belt and fight the Orphnoch King alongside the protagonist.
(I don't like Kusaka Masato, and I don't want Yuka to die. The Horse Orphnoch had it too rough, and he died in real life too. Let's let him live this time.)
I feel that it would be better for the author to create a cp for Shenguang. I recommend Kitazaki puppy and Shenguang falling in love and killing each other, or the loyal dog Yuji Kiba.