The Excalibur Build that this weapon is for

Prime the enemies with your secondary first, and then hit them with The [Exalted Blade], this way The [Exalted Blade] will inherit the heat status from your secondary.
You technically don't need [Molten Impact] for this, but without it, the damage from the blade is very low without prior priming. But if you are able to hit all of the enemies with your primer before you hit them with The Blade and don't need that extra safety net, you can swap [Molten Impact] with [Quickening].

The Secondary in Question

We're using both sacrificial mods to get as much crit chance as possible. Galv Steel makes our crit chance only 31%, and [Sacrificial Steel] alone makes it 48%. But the sacrificial set makes it 56%.

Primed Fury can be swapped with Berserker Fury.

Primed Faction mod can be swapped with it's non-prime variant.

Swap regular Elementalist for Galv Elementalist. I just put it there because overframe doesn't have the galv melee mods yet.

The Companion

The Companion Weapon