Base Class: Rogue
There are many who would take up the paladin's vow in order to smite evil. But as they march off to war clad in holy plate armour, there are those with the same goal in mind that stalk the shadows around them. Armed with stealth and all the radiant power given to their armoured compatriots, they act as holy assassins, shining blades in the dark that strike quickly and leave behind only a smoldering pile of smitten undead and demons.
The style of the raven's shadow was developed after one legendary rogue killed an ascendant god as part of a deal to his patron; the raven queen. His sacrifice inspired many to walk in his shoes and those once unworthy of the oaths and sacraments, were given a chance to partake in the war against evil that threatens all of mortality.
Eyes in the Dark
Starting at 3rd level, when you choose this archetype, the darkness becomes no obstacle to you but everyone bit as one to your enemies. You are blessed with greater sight with which to hunt your prey. You can see normally in darkness, both magical and non-magical, to a distance of 120 feet. You also proficiency in religion and arcana due to your oaths to hunt evil with holy power.
Smiting Edge
Starting at 3rd level, when you deal sneak attack damage to a creature, you can choose to have the damage be dealt as radiant damage. You also don't need advantage on the attack roll to use your Sneak Attack against an aberration, fiend, or undead creature. When you deal radiant damage to them in this way you roll d10's instead of d6's with that sneak attack.
Divine Senses
Starting at 9th level, you attain gifts necessary to stalk evil into the darkest of dens.You can cast detect good and evil without expending a spell slot.
You can do this a number of times equal to your charisma modifier. You regain all expended uses when you finish a long rest.
Enshadowed Mind
Starting at 13th level, your mind becomes an impenetrable darkness. You gain advantage on any saving throw you would make against divination or enchantment magics.
Additionally, you can no longer be frightened or charmed.
Banishing Backstab
At 17th level, when you deal sneak attack damage to a creature, you can force them to make a Charisma saving throw with a DC of 8 + your Charisma modifier + your proficiency modifier. On a failed safe, the creature is magically banished to a harmless demi-plane for one minute. One a successful safe, the creature can't be banished by this feature for 24 hours. Only one creature can be affected by this ability at a time.
You must concentrate on this banishment as you would concentrate on a spell. If you lose concentration, or if the minute passes, the creature reappears in the space it left or in the nearest unoccupied space if that space is occupied.
This effect does not work on creatures with legendary actions or resistances.