Card storylines

Some cards have a "storyline," for example Warrior Dai Grepher, written in the card descriptions and told by the art in featured artwork in spell/trap cards. In other words, it's a couple of cards with a specific relationship.

Many of these stories were detailed in Master Guide 2.

Warrior Dai Grepher
Born poor, Warrior Dai Grepher grew up with little else except confidence in his sword. Trying to find his way in the world, he was confronted on the field of battle by a mysterious woman who in short order became his greatest rival. Their first battle ended when a mysterious force disarmed them both; their next concluded with Dai Grepher being pulled into another dimension. He quickly found allies there. He is saved by his team's Spellcaster from a demon attack, at he cost of transporting him into yet another dimension.

There, he finds himself at The Paths of Destiny. Picking the path of light, he befriends a strange dragon, who grants Dai Grepher his power. Dai Grepher confronts and defeats a great demon, but at a heavy price, for his trusty sword is broken. He takes up the demon's sword as a replacement. Unfortunately, the demon was but an extension of the sword, which now sought Dai Grepher's body. Eventually, He submitted, becoming a rampaging monster until, at the height of his mutation, he was completely unrecognizable as his former self.

If he had taken the dark path, he would have turned into Dark Grepher.