Jesus, the Word of God.
Revelation 19:11 Now I saw heaven opened, and behold, a white horse. And He who sat on him was called Faithful and True, and in righteousness He judges and makes war.
12 His eyes were like a flame of fire, and on His head were many crowns. He had a name written that no one knew except Himself.
13 He was clothed with a robe dipped in blood, and His name is called The Word of God.
This rider of the white hoarse is Jesus. Back in chapter 6, some mistake that rider as Jesus, but he is the antichrist. Jesus is faithful & true. Finally, a righteous King. His eyes are like a flame of fire, seeing truth and burning away lies. His name, He has many, is the word of God. In the beginning was the Word, and the Word was God, as John told us. His wars are righteous.