Although Klaus appeared cool and awesome after killing the three-headed lion, he had to drain his reserve of Void Essence and two cores just to gain the upper hand.
Creating the clones was the easy part. He had long mastered that, and thanks to his unknown bloodline, he can go wild with his clones. So that wasn't much of a struggle.
However, keeping the main body alive when the Lion was killing more of his clones was the hard part.
He wasn't stupid.
Klaus knew the lion could easily locate his clones.
Once it managed that, the rest would be as simple as killing him with a single beam.
So he used the Void Law to augment his real body, and by using two cores, he created a much larger and more detailed illusion in which the main body and all his clones shared the same signatures.
Heat, energy, and even breath signatures were covered to the T.
That forced the Lion into a rather tight spot for a moment there. That time was all he needed to make his move.
