Paladin

Class description from D&D Beyond.
Silently, a dwarf stalks an orc war band celebrating a recent victory. Quietly, he whispers an oath, and two orcs are dead before they even realize he is there.
  Whatever their origin and their mission, paladins are united by their oaths to stand against the forces of evil. Whether sworn before a god’s altar and the witness of a priest, in a sacred glade before nature spirits and fey beings, or in a moment of desperation and grief with the dead as the only witness, a paladin’s oath is a powerful bond. It is a source of power that turns a devout warrior into a blessed champion.   A paladin swears to uphold justice and righteousness, to stand with the good things of the world against the encroaching darkness, and to hunt the forces of evil wherever they lurk. Paladins train for years to learn the skills of combat, mastering a variety of weapons and armor. Even so, their martial skills are secondary to the magical power they wield.

Notable Paladins

Playing a Paladin

The paladin class appears in the Player's Handbook, with additional subclasses printed in other sourcebooks, the paladin's stats can be found here.