Before being branded by the God Hand, Guts (Berserk) fought and defeated the sadist Apostle, Wyald and has only grown more powerful in killing the demonic monsters.
Witches like the Charmed One (Charmed) are powerful demon slayers due to their magic.
Dante Alighieri (Dante's Inferno) is a powerful and courageous human that can slay demons with his Holy Cross, a true relic, and Death's Scythe, a demonic weapon.
The Demon Killing Corps (Demon Slayer: Kimetsu no Yaiba) is an organization dedicated to protecting humanity from Demons and slaying them.
Being the eldest son of Sparda, Vergil (Devil May Cry series) is more than a match against lesser demons, allowing him to match and even surpass his brother Dante in battle.
As the son of Vergil, Nero (Devil May Cry series) is a demonic-human hybrid that possesses great demonic powers that allow him to slay the strongest demons who gained an increase in power from the Ascension Ceremony, and even hold his own against his uncle Dante.
Dante, and Vergil (DMC: Devil May Cry) are powerful demon slayers due to their nephalem heritage.
The most feared being in all of Hell, The Doom Slayer (Doom) can single-handedly defeat even the strongest of demonic creatures...
...wielding powerful strength, he can kill demons with his bare hands by tearing them apart.
Archangels (Mythology) are said to be powerful demon slayers because of their divinity.
Michael (Mythology) is said to be the most fearless archangel general, who has slain many fallen angels/demons in the war for heaven and is destined to fight the final battle against Satan/Lucifer and his remaining hordes.
Exorcist like Dulio Gesulado (Highschool DxD) are specifically trained to slay devils and fallen angels.
The Shadowhunters (Shadowhunters) are powerful demon killers sworn to protect mundanes from the shadow world.
Sam and Dean Winchester (Supernatural) have held their ground and even killed very powerful demons, something that many hunters before them claimed to be impossible.
Angels like Castiel (Supernatural) are natural demon killers with and without their angel blades.
Hellboy (Hellboy/BPRD) has single handily killed many demons throughout his career.