Lydia's relic was the most powerful of the novice group of Adventurers.
Nathan realized this after examining their relics one after the other during their times of training. While the Relics of the others were around Grade 9, hers was definitely a Grade 8, possibly a Grade 7. Since he wasn't an appraiser, Nathan couldn't accurately attribute a rank to it.
He knew it was powerful though.
The icy burst attacks which spread a severely cold mist freeze anything within it in seconds. Since their opponents were Stone Golems, the attack was even more effective on them.
"Stones have a very high cold conductivity. The attack should be even more active against them than on regular targets." Nathan smiled to himself.
There was, however, a problem with her Relic, it took too long to use a single attack. This is why Lydia stayed at the rear end to support the team once her Relic charged enough to launch her assault.