I recommend the novel "Orc Arena". The main character is an orc and has a gladiator system. Whenever someone is defeated in the arena, his ability will become the main character's ability. The person with the ancient bloodline was defeated, and the protagonist also possessed the power of this bloodline. After the fire dragon was defeated, the protagonist accidentally burped and released a dragon breath. This novel meets the requirements. The protagonist has powers similar to the King of Fighters 'Orochi. It is recommended. I hope you like this fairy's recommendation. Muah ~😗