Novel Twin Soul
There are many universes. Each universe contained countless realms. Each realm contained several planets. Some planets have different races of humans containing different skin and hair colors, different magical creatures, or different types of Demi-Humans. Some planets specialized in martial arts training while other planets specialized in magic spells casting.
In the World of Toria Continents, where all humans have blonde hair. Magic casters and Demi-Humans exist. Only one in every ten thousand people was born with an Elemental Soul, which helped them to be able to learn and cast magic spells. There are Fire, Ice, Thunder, Earth, Wind, Angelic, Demonic, and Conjurer Souls. One in every million people is born with a Twin Soul that allows them to learn Blood Magic and another type of magic of their choice, whether it is Fire, Ice, Thunder, Earth, Wind, Light, Black, or Conjuration Magic. However, the magic casters born with Twin Soul were forced to train Blood Magic if they wanted to level up in other Elemental Magic as well. Blood Magic required human blood for training. Animals' blood, magical creatures' blood, or the blood of Demi-humans can't be used.
Toria Continents were once greatly suffered under an evil level 100 Saint-tier magic caster that used Blood and Fire Magics. The evil Saint-tier Blood Mage was defeated after a deadly battle between her and another two thousand Saint-tier magic casters. Over eighteen hundred Saint-tier Mages were lost in this battle but they later found out that they didn't actually defeat that Blood Mage because she somehow revived herself after being killed. The history book was written that evil Saint Blood Mage can create two extra versions of herself. As two versions were killed in the battle, the third version escaped and later revived the other two versions.