Roman religion was very complex, and its concepts are so multifaceted they can be difficult to grasp. One key point was that every person, place and thing could have its own genius or Juno (the female equivalent in many ways, but distinct; named for the Roman queen of the gods), a spirit that made people thrive and succeed if it was given proper worship. The various gods adopted and originated by the Romans could take many guises and went by many names over the centuries of the civilization’s existence, and in some cases it is debatable as to whether a god was actually a separate entity or just a manifestation or appellation for another. Regardless, Romans were all extremely pious, and religious duties were paramount for all heads of household, from the lowest of the slaves all the way up to the senate and eventually the emperors. Augury, devotions and sacrifices were given very serious weight, and no one could advance in society without demonstrating their faith and devotion to the gods. When the Romans truly became an Empire, the emperors themselves were cast as embodiments of the various gods and worshipped in an Imperial cult.
In a D&D game with Roman influence, clerics and paladins would be not at all out of place amongst the Imperial legions, as military leaders were often religious leaders as well. In some cases, generals would offer their own lives as a sacrifice to the gods to ensure victory, and military losses were often attributed to failure to properly please the gods and the genius of the military units involved. The War domain could be appropriate for these officer-priests, but its spells tend more toward the flashy and overtly offensive, and I wanted a more leadership based domain for such a campaign, so I designed the one below. It makes for an excellent party leader or battlefield commander.
Additionally, here is some brief information on a few Roman deities that had no Greek equivalents:
Janus – The dual-faced Lawful Neutral god of beginnings, gateways and transitions – Suggested Domain: Knowledge
Mithras – Neutral warrior god who was worshipped alongside Sol, the Sun God; had a powerful mystery cult and was popular with the military – Suggested Domains: Imperial, Trickery, War
Sol Invictus – “Unconquered Sun” – Neutral sun god, also a patron of soldiers – Suggested Domains: Light, War
Saturn – Lawful Good god of plenty, wealth, and renewal – Suggested Domains: Life, Nature
Quirinus – “Wielder of the Spear” – Lawful Neutral war god who had many possible origins, including being a deification of Romulus, one of the founders of Rome – Suggested Domains: Imperial, War
The Imperial Cult (worship of the emperors as gods or incarnations of gods) can also be worshipped by a cleric instead of a god; the religion is considered Lawful Neutral and is most likely to select the Imperial domain, below, but can choose any domain.
You worship the genius of the Roman Empire itself, particularly the military, and your divine powers lie in the command of others. You likely serve as a priest among troops of the legion or as a religious advisor to a general.
This domain could be adapted to other imperial cults throughout history, or any deity whose portfolio includes nationalism and militarism.
Imperial Domain Spells
1st – Command, Heroism
3rd – Beacon of Hope, Hold Person
5th – Fear, Haste
7th – Banishment, Private Sanctum
9th – Dominate Person, Greater Restoration
At 1st level, you gain proficiency with martial weapons and heavy armor.
Starting at 1st level, you can give commands in battle that impel your allies into action. As a bonus action on your turn, you may direct an ally who can see or hear you to attack. The ally can use its reaction to make one weapon attack against an enemy you can both see.
You can use this feature a number of times equal to your Wisdom modifier (a minimum of once). You regain all expended uses when you finish a long rest.
Channel Divinity – Invoke Dominion
Starting at 2nd level, you can use your Channel Divinity to command creatures to move aside or charge forward.
As an action, you present your holy symbol and shout a powerful command. Allies within 30 feet that can hear you may use a bonus action to take the Dash action during their next turn. Each hostile creature within 30 feet that can hear you must make a Wisdom saving throw. If they fail that saving throw, their speed is reduced by half and they cannot take reactions until the end of your next turn.
Improved Guiding Voice
Beginning at 6th level, when you use Guiding Voice to grant an ally an attack, they add your Wisdom modifier (minimum 1) to the attack and damage roll.
At 8th level, you gain the ability to infuse your weapon 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 damage of the same type dealt by the weapon to the target. When you reach 14th level, the extra damage increases to 2d8.
At 17th level, your will is supreme. You cannot be charmed or frightened, and you have resistance to psychic damage. Additionally, when you cast a cleric spell with a duration of “Concentration, up to 1 minute,” you may choose to have that spell’s duration extended to “Concentration, up to 1 hour.” Once you extend a spell this way, you cannot do so again until you finish a long rest.