Here is my giant killer Paladin’s Sacred Oath for DnD 5e. Let’s follow a lesser known medieval hero who dominated a giant just to carry his gear!
Path of Astolfo
The Path of Astolfo is an oath taken by some of the knights long ago who followed a leader known as Charlemagne. Their leader and his knights are lost to the ages, but few find his name and fewer take up his mantel. A defender of the weak and an especial protector of those locked under magical manipulation, Astolfo was rescued by magic and understands that magic in all its forms might not necessarily be evil. Known for his dominated giant foot servant and his golden lance, Astolfo was a traveler who went to the moons and back to save his friend then become a defender of an entire city. Those who follow his path wander the countryside attempting to help all those they find, even using magic to coerce those who might be irredeemable to become righteous.
You gain oath spells at the paladin levels listed.
||Shield of faith, sanctuary
||lesser restoration, suggestion
||remove curse, dispel magic
||dominate beast, guardian of faith
||dominate person, greater restoration
When you take this oath at 3rd level, you gain the following two Channel Divinity options.
Horn of Charm: As an action, you blow a magic horn causing its song to bend the will of even the most hardened creatures. At 3rd level this action acts as if you cast charm person using your spell save DC as the DC for this effect. At 7th level, the effect of the horn can be as if you cast dominate beast. At 10the level the effect of the horn can be as if you cast dominate person. Finally at level 15, the effect of the horn can be as if you cast dominate monster.
Golden Lance. As an action, you present your weapon and speak a prayer asking for the force of your forebearers. For one minute or until you are knocked unconscious, your weapon glows with a golden radiance. When a creature is struck with your weapon as part of an attack, the target must make a Strength saving throw (DC equal to your spell save DC). On a failure, the target is knocked prone.
Mount of the Master
Starting at 7th level, you gain a nightmare mount. Its AC is equal to your AC and has hit points equal to a half your hit points. As an action you can have it make one attack, but can use your move action to command the creature to move as normal. It loses the Ethereal Stride ability, but does not make hoof prints to be tracked.
At 18th level, the nightmare gains a flight speed equal to its land speed.
Resistance of the Leader
Beginning at 15th level, you gain advantage on all saving throws against spells.
Bulwark of Paris
At 20th level, as an action, you can follow your master and become a true defender of the people. For the next minute, increase your AC and saves by 3. In addition, all allies within 30 feet also gain these benefits. These benefits last for the duration, you voluntarily end it, or until you are knocked unconscious.
Once you use this feature, you can’t use it again until you finish a long rest.