The defeat of Kallamar was the most monumental for Diana. Sure, the trip to find the cowardly Bishop in the strange, watery depths of Anchordeep was more or less the worst yet, due to the various traps that awaited her and the countless skeletons anchored to the sea bed was a grim reminder what lengths Kallamar demanded his sacrifices from his cult. For that matter, while Leshy's cult fought for fear of their lives, and Heket's with full bellies, Kallamar's showed no signs of fatigue, weakness or illness. They were the first to push Diana to her limits, able to fight as if fully rested.
But for the first time since she began her crusade, Diana finally saw more colors than red with full clarity. The sea bed is a absolute ecosystem of fish with plentiful meat, countless seaweeds that could serve as food or medicine, and coral grows in countless colors and shapes. But it was the crystals, the way they painted the seafloor in a rainbow when the light touched them, that made her finally take a moment to pause.
Not for long, mind you, but it is notable when even the most devoted crusader will stop and take a moment to savor their surroundings rather than push themselves to the breaking point. It made her want to settle her personal vendetta all the more... The squid had unleashed the plague on her village, made her watch as everyone around her grew too sick and weak to fight back when the Old Faith came, or made them die around her. He took her sight from her... Now she'd rip out his heart and take his Crown.
Naturally, Diana hadn't exactly learned her lesson from the previous two Crowns, and how they'd fight to be worn by her since she proved herself more worthy than the Bishops. At least, by whatever alien logic the Crowns think with, that is. For yes, the Blue Crown, when atop her head, does indeed cause the Lamb to become a real splendor of beauty, even making her dainty little horns grow into large, spiraled ones like a ram or spiral seashell that shine like rainbows. It just comes with the side effect of the Blue Crown's vision, which is radically different from the others...
And frankly, it's the only Crown that disturbs Diana when she wears it. Because now she can SEE what Kallamar did, and why he was such a coward.