Radagon is a Runic Magic , he attained that power as a child and has been honing that skill for ages by slaying wild beasts.

Powers:

Runic magic can be used to create elemental attacks(fuse them also)

Envelop part or full body in element

Can be written in air or on an object(like paper)

Used to enhance body or weapons

Used for utility purposes (small heals, increasing growth of crops, increasing good luck)

Higher runes can summon monsters but need blood sacrifice

Hand to hand combat techniques(He learned and developed many to be able to defend even without using his weapons)

Weapon: il-ium

Looks like a sword enhanced by runes, but also has ability to be used as a whip, it can use runic magic to make blades move like a chainsaw and between blades heat can be produced.