The good thing about tier five spells was that they worked the same way as true magic so the Nightwalker could still salvage the situation by consuming enough mana to cleanse Lith's and repair the armor.
Just like Lith wanted.
The previous Final Sunset had served the same purpose. To force the undead to consume the mana stored in his blood core to purge the God of Nightstorm of the foreign energy signature.
"Let me guess, a Source Magic spell costs way more than two tier five spells." Lith said. "With no breathing technique and no more thralls for a sip, you won't last long."
Thanks to the elemental crystals, Lith had consumed only a fraction of the mana necessary for his spells whereas the Nightwalker could only tap into his own reserves.
"True, but it's long enough!" Ulma restored the God of Nightstorm and conjured another tier five Source Magic spell, Dark Mastery.