Yeah got the drop.
Captain ability Entire crew's ATK x1.5
Special: For 1 turn halves all enemies' DEF (15 turns)
800 ATK, 1500 HP
He's a nice INT DEF reducer when you don't want to stall for Helmeppo's 25 turns.
Nice, congrats!
I read a strategy on Reddit that, more-or-less, guarantees a win.
You need:
Golden Hammer Usopp
Smooth Alvida
Mirage Tempo Nami
Basically, you use Golden Hammer Usopp's Special Ability to start the final boss stage [Round 1]. Then, on Round 9, use Alvida's Special Ability, which reduces damage by 50%. On Round 15, use Mirage Tempo Nami's Special Ability and then, on Round 16 use Golden Hammer Usopp's Special Ability once more. Rinse/Repeat. You do need to heal 3200HP every 15 turns.
Unfortunately, I've already evolved my Mirage Tempo Nami, but I do have a max-skilled Golden Hammer Usopp. I should be able to use his special, then Alvida, then his again. Not sure though, I can't remember what the CD on Smooth Alvida's special is...
Edit: Never mind, it's 15 turns. I'll only be able to use it once in-between Golden Hammer Usopp delays. With a dual Gear Third Luffy team, though, I should be able to kill it before I need a second 80% reduction. It would be the initial 6 rounds + 3 delayed [Golden Hammer Usopp] + 1 mitigated [Smooth Alvida] + another 6 rounds [after attack] + another 3 delayed [Golden Hammer Usopp] = 19 rounds. That should be enough, unless I really mess things up...
Either way, I'll probably attempt it next week. I'm still working on leveling up my Gear Third Luffy [and other units], and it's not as though I need a Rainbow Dragon right now. It'd be nice to have that Rainbow Gem, but I can always grab it next week when I find the time to do so.