Someone help me find this story pls

I confused the story with this webtoon. What i can remember that mc is always sick and have a twin but the twin died after being carried by the river. The mc's father is very powerful swordmaster. Mc attends school just like this and make some incredible friends (spoiler? One of them is red dragon). The most prominent plot i remembered is that mc died after protecting crown prince and somehow come back alive with some kind of spirit's power.

Help me pliss, i tried finding this plot in this webtoon and couldnt, which then i realized it was a different webtoon ╥﹏╥