Phantom of the Abyss all the way, it can just dodge half a battle.
Though dragon is my fav splinter - mostly because of how they have a good mix of melee, magic, and range + can be used with other splinters. So if I have a monster thats good for a particular ruleset, i can go with some strong Dragon monsters + whichever other splinter for that particular monster.
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RE: (ended) 250 DEC Giveaway - Very easy, just reply with your favorite card and splinter!