The Guardian Domain

Just as clerics act as a guide to others on their spiritual walk to divinity, they too must be protected from evil. May it be temptations, worldly threats, or a spiritual attack, only those under the watchful eye of God can truly be safe. But even the faithful are impure at times, they must be watched over so they can continue to bring healing and guidance to others. Those that serve in the Guardian Domain seek to protect people from all that would do them or their allies harm, and just as they provide aid, they too will be saved as they've saved others. For all good will shall be returned in full under the watchful eyes of the powers controlling the cosmos. Only those that survive can learn the path to becoming purified, and as the pillar of virtue and the rock for which others will stand, it is the duty of those in the Guardian Domain to uphold the sacred teachings and preserve life. 

Bonus Proficiency

When you choose this domain at 1st level, you gain proficiency with heavy armor.

Sacred Covenant

You gain a companion similar to the Ranger's "Primal Companion" at the 1st level. This companion can take on the form of whatever you wish, but it must be a being that ranges from Small-Large. If your alignment is good or neutral the companion can shimmer with radiance or appear normal while dealing radiant damage, if your alignment is evil you can have it steeped in shadows and deal necrotic damage. The entity is friendly to you and your companions and obeys your commands as it is directly tethered to your well being. 

When choosing a companion use its own stat block but remove all multi-attacking or spell casting options. Instead of its proficiencies, use your own proficiency score from the cleric and add it to ability checks and saving throws. For HP, use (5 )+ 5 times your cleric level. All special characteristics of the companion are intact from their stat block, but if you choose a being that can normally wield weapons, they may be given weapons to use in combat. The companion also has access to spellcasting when they reach 3rd level, learning 1st level spells. As they level up they will unlock spells at the 5th, 9th, 13th, and 17th level.  The companion can concentrate on their own spells.

In combat, the companion acts during your turn. It can move and use its reaction on its own, but the only action it takes is the Dodge action, unless you take a bonus action on your turn to command it to take another action. That action can be one in its stat block or some other action. You can also sacrifice one of your attacks when you take the Attack action to command the companion to take the Attack action. If you are incapacitated, the companion can take any action of its choice, not just Dodge.

If the companion has died, it can return to life if the cleric uses a 1st level spell slot or higher to bring it back. The companion returns to life after 24 hours with all its hit points restored. The companion also vanishes if you die.

Companion SpellCasting

The companion gains the following list of spells to use at the following levels a Paladin would unlock them, 3rd level, 5th level, 9th level, 13th level, and 17th level. 

Cure Wounds, Searing Smite, Branding Smite, Warding Bond, Spirit Shroud, Aura of Vitality, fire shield, Death Ward, Destructive Wave, Raise Dead

Channel Divinity: Sovereign Protection

You utter a prayer or present your holy symbol to bestow (5) + 3 times your cleric level in temporary hit points and a +1 to the AC of one living being within 30 feet of you for 1 day. These hit points can be stacked upon other temporary hit points granted to creatures, but must be applied after. If another creature tries to apply temporary hit points after this feature is used it will fail.

At the same time this feature is used, you may disperse any temporary hit points you or your companion have acquired to any creatures within 30 feet of you at the time of activation. You may not take another characters temporary hit points unless they give permission, but may give it to any creature you see fit.

Intercessor

As a reaction, the cleric can use the following to try to save an ally from danger if it is prepared and known by the PC at that time: shield, shield of faith, counter spell, death ward, and antilife shell. You may do this a number of times equal to your wisdom modifier and must complete a long rest to regain uses. Each use will use a spell slot and if the spell is being cast as a reaction the distance is 30ft; regardless of the previously stated range, longer or shorter, when these 5 spells are used as reactions this is their default distance. When being cast normally the previous rules will apply. 

Also, your companion links to you and your party when within 30ft, sensing what your needs are. The companion gains a second reaction on top of the bonus action used to control them. They can use the reaction to give advantage on a saving throw, attack role, or provide an attack of opportunity if an enemy is within 5ft of the ally. 

Divine Strike

At 8th level, you and your companion gain the ability to infuse your weapon and physical strikes with divine energy. Once on each of your turns when you hit a creature with a weapon attack, you can cause the attack to deal an extra 1d8 radiant damage to the target. When you reach 14th level, the extra damage increases to 2d8. If you are an evil alignment you may use necrotic damage

Guardian Angel

When you reach Lv 17, you and your companion are able to channel such divine power that you can ensure the longevity of a being you choose by acting as the agent of mercy or protection. When you or your companion see a being fail a saving throw or ability check, you may use your reaction  give them advantage on the roll. They can choose the higher of the two rolls. This feature can be used a number of times equal to your wisdom modifier. You may only regain uses after completing a long rest.