Legend says that the enigmatic Millennium Puzzle will grant one wish to whoever deciphers its ancient secrets. Upon solving it, high school student Yuugi Mutou unleashes "another Yuugi," a peculiar presence contained inside. Now, whenever he is faced with a dilemma, this mysterious alter ego makes an appearance and aids him in his troubles. Wishing to unravel the mystery behind this strange spirit, Yuugi and his companions find themselves competing with several opponents in "Duel Monsters," a challenging card game used by people seeking to steal the Millennium Puzzle in a desperate attempt to harness the great power within. As the questions pile on, it is not long before they figure out that there is more than pride on the line in these duels. [Written by MAL Rewrite]

Shiraishi Urara is the top student in her school. One day, due to an accidental kiss, Urara finds herself in the body of the school delinquent, Yamada Ryuu! In trying to switch back to their own bodies, Urara and Ryuu discover that kissing causes them to switch bodies, which leads to their discovery that there are 7 witches in their school. They soon try to uncover the identities of the 7 witches...

The Urusei Yatsura story comes to a climax in this animated retelling of the final Manga story (although not the final movie). Lupa, yet another one of Lum's fiancés, arrives on the scene, and Lum and Ataru have to repeat their game of tag in order to prevent the Earth from being destroyed.

All Ataru has to do to win is say "I love you" the three words he has steadfastly refused to say to Lum. Will he admit his true feelings and save the Earth? Or will his pride doom it to destruction?

(Source: AniDB)

The episode bundled with the 13th volume is about the Sumo competition that held at Tempest for the first time, suggested by Rimuru. The three-part OVA bundled with the 14th, 15th, and 16th manga volumes is an original trilogy written by Fuse. Rimuru has been teaching Shizue's students at Ingracia Kingdom's Freedom Academy. The time has come for the school's annual outdoor training event, where the students will test their combat skills in the field. Rimuru is determined to win the competition and take home the prize money, but he is challenged by Jeff, an honorary teacher who sees Rimuru as a rival. The competition is underway when suddenly an unexpected enemy appears!