3: Protective Magic, Channel Divinity
7: Roots of Stone
15: Shield the Vulnerable
20: Living Fortification
Enduring Stone. Those you defend must be able to trust in your resilience.
Stable as Stone. You must be consistent, dependable, and fair in your dealings. Let no hint of caprice or pique cloud your judgment, but cleave to what is right.
Strong as Stone. You must be willing to shoulder far more than your “share” to walk this path.
Will of Stone, Not Heart of Stone. You must be incorruptible, implacable, and uncompromising, but this must be tempered with empathy and compassion. Strength without goodness is worse than weakness.
Add the protection school of magic to your list of oathbound spells
At 3rd level when you choose this archetype, you gain the following two Channel Divinity options.
Earthen Resolve. When you are subjected to an effect that would alter your behavior (such as becoming charmed , confused , or frightened ) or that would allow another creature to dictate your actions (such as the command spell), you can use your reaction to negate that effect on you.
Rock Skin. You can use an action to cover yourself in a magical layer of gray stone plates. You gain temporary hit points equal to your Oathbound level + your Charisma modifier (minimum of 1). The temporary hit points last up to 1 hour. While the temporary hit points remain, critical hits against you are treated as normal hits.
At 7th level, while you are standing on a solid surface, you can use a bonus action to root yourself in place. While rooted, your Speed becomes 0, the ground within 10 feet of you becomes difficult terrain, but whenever an effect would move you or knock you prone , you ignore that effect. In addition, while you are rooted, a creature you hit with a melee weapon attack must make a Anchor save against a DC of 10 + your proficiency bonus. On a failure, the creature’s Speed is reduced to 0 until the end of its next turn. You can end your rooted state as an action.
At 15th level, when a creature you can see damages you or a creature within 5 feet of you with a weapon or spell attack, you can use your reaction to reduce the damage by an amount equal to 1d6 + half your Oathbound level (rounded down). You must be using a shield to use this feature.
At 20th level, you can become a living fortification—immovable and unbreakable. You can use a bonus action to become an immovable object, gaining the following benefits for the next minute:
You gain resistance to all damage.
You can’t be moved unless you choose to be, even if targeted by an effect that would teleport you or if the surface you are standing on gives way. If this results in you standing in midair, you gain a fly speed of 10 feet until the effect ends. If you are still in the air when the effect ends, you fall normally.
You can't use this feature again until you take a long rest.