Join the Tag Duel tournament.
In order to get this form of the infamous red-eyed beast, of course, you need to participate in the event. By fighting random NPCs in Duel World you can win Friendship Letters, which you can use to fight inside the Tag Duel tournament, featuring familiar faces like Yugi Muto and Jaden / Yubel. PvP Battles also grant you such items, up to 3 times per day.
As you progress through the tournament, you will collect lottery coins which you spend on the lottery of course, with some great rewards on top of that. Including the Red Eyed Dark Dragon! Also, the higher your Duel Rating Score, the more coins you will get, so trying to build a deck that will easily handle tournament opponents is highly recommended. There is always a chance that a Challenger will also spawn after a Tag Duel match, which will earn you extra coins if you beat them. Be sure to pay attention to such a chance.
Additional copies.
Additionally, you can get an additional Red-Eyed Dark Dragon through the EX card trader. If you've gathered the necessary EX Jewels, you can exchange them for a bonus copy of the map.
Finally, another additional copy can be obtained by winning the third round of the GX Cup, within the event, so try to finish it until the end.
The map itself is rather outdated at this point, but its offering as a big reward during an event could indicate that more support is coming for our beloved black dragon. We can only wait and see, so do our best for this event, to collect at least the two copies of Red-Eyes Darkness Dragon (in case our luck in the lottery doesn't seem to do the trick).