Thanks for using my sketch! :D I loved using Phantom of the Abyss when I had him. Won me many games, especially in lower leagues. He is actually especially good in the back position with a magical tank up front if you aren't sure what kind of damage your opponent is bringing and the mana will allow it. Since most sneak monsters are melee, being in the last position almost entire negates their team if they go that route. And if they go magic damage you still have a decent attacker while they go through the magic tank. And if they bring general physical attacks and manage to get through to him he can still win the whole game from the first position too.
Really fun card.