The All-Kill Array was a good example. It was initially the greatest defensive weapon of the Tower of Dusk, but its power could not be released to the maximum, simply because its mana source was weaker. Otherwise, it would've been impossible for the Dark Blade to hurt Tower of Dusk once the All-Kill Array was activated.
During the trip to the Haiga Mountain Range this time, Lin Li obtained plenty of magical crystals, and that included the Green Dragon Crystal that he obtained after excavating the green dragons' graveyard. The Dragon Crystals were all above the Legendary level, and the level-22 magical crystal was way stronger than the Salamander's Magical crystal that was being used by the Tower of Dusk now. Lin Li had plenty of magical crystals anyway, so he could afford to spare a few.