Who was called the Bulgar slayer?

The title "Bulgar Slayer" refers to the Byzantine Emperor Basil II, who reigned from 976 to 1025. He earned this moniker due to his military campaigns against the Bulgarian Empire, culminating in the decisive Battle of Kleidion in 1014, where he achieved a significant victory. Basil II's relentless efforts effectively subdued Bulgarian resistance and expanded Byzantine territory, solidifying his reputation as a formidable military leader.