How to use:
So when you start a mission you use wellspring to get energy startup. Then find a crowd of enemies. Use Radial Javelin to proc your [Furious Javelin] and get extra melee damage. Then use your Radial [Howl] to get the extra finisher damage on your [Exalted Blade]. Now that you have your buffs, equip [Exalted Blade] and cast Marked for Death on one trashy unit. Use a finisher on the marked enemy and because of your augment buffs, it should one tap and deal the sameish damage to everything else around it.

Shards:
If you have shards, I would recommend using full crimson with the melee crit damage or the ability strength buff for better numbers. Otherwise, if you feel you are taking too much damge then use 3 crimson and 2 azure with the amour buff for better protection. Amber shards with casting speed is useful because this build is utilising ability spam nuking.

Melee build:
On your [Exalted Blade], make sure to put all the good finisher mods and both sacrificial mods for damage. [Organ Shatter] as well for more damage. Then put attack speed as well because we will be spamming finisher attacks a lot.

How it works simply put:
[Furious Javelin] gives extra melee damage. [Radiant Finish] gives extra finisher damage. And Marked for Death applies damgage to every visible enemy in the range. Therefore with the extra melee and finisher damage you use a finisher on a [Marked Target] which has been blinded (Radial [Howl] stuns enemies and makes them viable for finishers) and that attack deals way more damage but also applies it to other enemies. Therefore maximum nukage.