Bloodbath for a Throne

The next time you hit a creature with a melee weapon attack during the spell's duration, your weapon nearly shatters on your grip as pure divine power flows through it, causing you to deal an additional 2d8 radiant damage on a hit and forcing all hostile creatures within 10-ft of the initial hit target to pass a Constitution Saving Throw or take the same amount of damage. For any creature that is killed or knocked Unconscious from this damage, all hostile creatures within range suffer an additional 2d8 radiant damage and then are inflicted with 4 Rupture count, as the space around you crackles and breaks.
At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the radiant damage dealt by all effects increases by 1d8 and you deal an additional 2 counts of Rupture for each slot level above 1st. 

Rupture:
A creature suffering from the Rupture condition takes extra dice of damage whenever they're attacked equal to half their stacks of Rupture, rounded up. The additional damage die depend on the attacking creature’s Proficiency Bonus, being d4 at +2 Bonus, d6 at +3 Bonus, d8 at +4 Bonus, d10 at +5 Bonus and above.
Once an attack successfully hits and the condition is triggered, they lose all of their stacks of Rupture and the condition ends.

Ex: If a creature suffering from 5 would suffer a hit from a creature with a +4 Proficiency Bonus, they would take an additional 4d8 damage.