Sephiroth represents vengeance and chaos in all forms, as his story arc follows his creation, rebellion, and finally attempts to ascend to godhood
When Hildibrand Manderville dies, you may cast it from your graveyard as an Adventure until the end of your next turn
Whether it's fishing, blitzball, or even playing cards (when I learned Magicked Card was a mount, I knew it had to be a card), there's always something else besides combat to do here
There may even be a Standard deck here with an early Sazh's Chocobo that Summon: Fenrir makes swole real soon
Enter a magical realm
It's a tall order, but getting both Vault Doors into play would mean all of your locations and characters would have +2 resist, and that would be an incredibly difficult thing for your opponent to overcome