Thunderdevil King was the son of a king, and had entered the first spirit base only a few months prior. Wielding the powers of thunder, he was renowned for not losing a single time. As such, he was given the title Thunderdevil King.
This king proclaimed that he was brimming with the very essence of thunder, and that he was an organic descendant of the element itself.
This was only partly true, but his father was extremely proficient in wielding thunder powers. His mother was a spirit princess that also excelled in wielding thunder powers.
On the day Thunderdevil was born, he came into the world crackling with the charge of electricity. As such, it prompted his father to boast and declare that his son was the strongest being of thunder to ever exist.