Skuld's approach to the Valkyries did give her an idea... one that could actually be implemented before they returned to the normal world. After all, the explosion had done plenty of damage, and magic was much better for hitting multiple targets very quickly. Having magic resistance would help against magical attack--but if it was reduced slightly and the magic was strong enough, you'd get worn down by volume of firepower...

With Nero jumping away to maintain distance, there was time for Skuld to fire--and when that happened, no doubt distracting them again, that was when the other Caster planned to strike: letting the valkyries fly again... at the cost of reducing their magic resistance.

At which point being able to incant powerful spells in a single word was going to be very useful to match Skuld with a laser barrage, because there were only a few seconds left before this all finished.