Choi Yeonjun.

There were four elements in this world: fire, water, earth, and air. Almost everyone was allowed to interact with each other, except... fire and water, you know why. That's why these two elements were often separated; no one knows what will happen if these two elements merge.

The university was bustling with life. Lessons on mastering your element and everything in that spirit. Yeonjun possessed the fire element, was quite popular in his class, and was famous for having almost 100% mastery of his element (not all of them, of course, so sometimes he could lose control, for example, in a fit of anger). Beomgyu possessed the water element, a very active and sometimes capricious guy. But they never crossed paths with Yeonjun, only once at the beginning of the year, where all the elements were, and then, after they were separated, air and earth were the luckiest, you could communicate with everyone.