Notes from author
Karmic justice has a Spell MV of 3 (0.2 higher than Wrath of the Gods), and it is calculated based on the int+faith scaling of whatever's in the right hand at the time of the explosion, and you get 4 casts. Tin crystallization catalyst offers the highest scaling you can get, with 254 at base stats. Now, add in the 1.2 multipliers from the Ring of the Sun's Firstborn and Crown of Dusk, the damage calculation goes:
3 * 254 * 1.2 *1.2 = 1097.28 pure magic damage in a 4x4 sphere around you. At level 57. How to activate it though? After all, we're a squishy little split caster, however will we be able to... wait. Karmic Justice activates whenever 5 instances of damage are taken within at least 3 seconds of each other... including through a shield. Now what shield boasts light weight, high stability, low requirements and close to but not 100% physical block? The Eagle shield. Now we have a magical Nuke, the way to cast it, and a fairly good way to negate most damage while we're at it. What do we do if 4 casts of a 1097 pure magic damage spell isn't enough? First of all, *what are you fighting* second of all, not to worry! Great soul arrow does about 550, and Homing Crystal soulmass, if everything hits, does
254 * 1.2 * 1.2 * 1.15 * 5 = 2103.12 damage (although magic defense is applied to each hit individually). Also, Dark Bead. I'm not calculating how much damage dark bead does, it's Dark Bead. Screw you. Anyway, if by some miracle none of that worked... I guess shieldpoke with Velka's rapier. If you want, you could put 3 more points into attunement and any pyro flame and grab Power within for a 1.4 multiplier to the above damage and some stamina regen for when you use the shield but... come on. That's putting a hat on a hat. ALSO, power within is a body buff and would not stack with Karmic Justice.