"Beep, analysis completed. In total, thirteen thousand eight hundred and ninety-one Guardian Monument's Spell Models have been reconstructed."
The Matrix had completed its analysis with a reconstruction of more than ten thousand Spell Models. Back then, there were only about eleven thousand Furious Flame's Spell Models so, both Spell Models were about the same.
Among the reconstructed Spell Models, Merlin first chose those with a higher compatibility. Next, from the highly compatible Spell Models, he chose those with excellent stability and power.
Merlin was already greatly familiar with the process of choosing a Spell Model. He needed to consider compatibility, stability, and power, so Merlin quickly got the Spell Model he was satisfied with. However, Guardian Monument was less compatible with Zero-level spell Earth Guard than Furious Flame with Fireball.