I suppose a little context is in order, since it didn't save my summary. This is a crossover of Yu-Gi-Oh Duel Monsters with Yu-Gi-Oh 5ds, as you can tell. So here's the time frame. The DM time period shown takes place after the events of The Dark Side of Dimensions, but treating it as if it were an anime event, rather than a manga one. The 5ds characters are taken from a time after their series, between the development of Fortune and the timeskip showing where everyone(save for Yusei) is after the events. However with the liberty of Akiza retaining her Psychic Duelist abilities.
A guest user asked me why Obelisk the Tormentor would be defeated by the Crimson Dragon, so here's a little insight. First of all, it was a Ka battle of sorts, and i'm using a system similar to Yu-Gi-Oh R's Divine Scale. Here's how I rate it.
God Cards(Egyptian, Wicked, Nordic) are the first two of five "Tiers"
Tier 1: Obelisk the Tormentor, Slifer the Sky Dragon, The Wicked Eraser, the Wicked Dreadroot, Thor/L