Hmmmm... from all the unplayable characters... I'd have to say I find Moria to be the best. Since most of the specials that lead into Partner Strikes gather up all surrounding enemies into a single area (Nami's Tornado Tempo, Crocodile's Sandstorm, or Blackbeard's Dark Matter), Moria's follow-up special seems to have the biggest attack radius. Sure it's nothing really special, just 4-5 Tsuno-Tokage shooting out of the ground. But from what I've seen it's damage output is second only to Jozu's Brilliant Punk.