Lazarus

He had remained quiet since the start of the challenge, but it was probably time to speak up. "Glowing rain could be referring to the reflection of light off of hail. However I believe you're right. It's ash. It fits the bill." His arms remained folded.

Shujin
His team was pretty good at these. However when this riddle came up he facepalmed. He knew the answer. In court it was the high judge's favourite riddle. "The answer is watermelon. I can confirm that as 100% definite."