Book of Yuno

Black Clover: Book of Yuno (ブラッククローバー ユノの書) is the third light novel of Black Clover.

Summary

 * 1) Gold and Black (金色と黒): Yuno, Klaus Lunettes, Mimosa Vermillion, Yami Sukehiro, and Asta go undercover to investigate a matchmaking party for nobles. Their goal is to gather information on the trade of illegal magic tools, specifically one known as the "Original Sin" which takes the form of a white grimoire. They find a nobleman named Zable in possession of the tool, then subdue him and destroy the grimoire. Once Zable's mind clears, he informs the Magic Knights that the Original Sin makes copies of itself and that his was one of those copies.
 * 2) The Person Named Julius (ユリウスという人物): While patrolling a forest because of a reported sighting of another user of the Original Sin, Yuno stumbles upon an embarrassing secret about Wizard King Julius Novachrono: he has been taking care of and doting on a recently orphaned and injured baby flame boar that he's named Graham. Since he's so busy, Julius asks Yuno to help him (secretly) watch over the boar. Then, a fleeing bandit who wields a copy of the Original Sin kidnaps Graham. The copy is destroyed, and the boar is saved and eventually returned to the wild.
 * 3) The Sun Doesn't Set For Troubled Women (こじらせ女子は黄昏れない): Sylph searches for a gift for Yuno in town when she runs into Noelle Silva and Charlotte Roselei who are both in disguise. They are also looking for a gift for their "important person." The three decide to help each other shop, but their trip is interrupted by the appearance of another user of the Original Sin. This time, the magic tool has hijacked the user's body like a parasite.
 * 4) The Disappeared Hero (消えた英雄): Captain William Vangeance organizes a festival so that the citizens can get to interact with the Magic Knights. Yuno helps to patrol the event, and Vangeance tells him that traces of mana from the Original Sin have been detected at the festival. The user is found, but they discover that they are not dealing with a copy - it's the original. Although proving to be more difficult to deal with than the copies, the magic tool is destroyed. Vangeance confirms details with the other soul inside himself: the tool was originally a prototype created centuries ago by the elves and humans that revived unexpectedly and became corrupt from the original intentions behind its creation. The festival goes on, and everyone awaits that important day.

Extra Pages: What Yuno did on his day off while Sylph was in town in chapter 3.

Trivia

 * The background of the cover is one of Sylph's pages from Yuno's grimoire.