Is this a filler episode?
No, it's canon. The events of this episode are from Weekly Shonen Jump #43 (September 22, 2014) and #45 (October 6, 2014). (One Piece was off for the week of Weekly Shonen Jump #44.)
Why does Law want to kill Corazon?
This is how they met. "Corazon, this is Law. Law, this is the trash heap."
Whose childhood do you think was worse: Robin's or Law's?
Law and Robin had similar childhood tragedies. Both of their families and lands were destroyed by the World Government, but I think Robin had it worse. Law was "adopted" by another family — albeit the sinister Donquixote Family. Robin was running for her life long into adulthood. Think back on Jaguar D. Saul and Aokiji, and the later events with CP9....and the return of Aokiji.
Which Donquixote Pirate had the most noticeable change since the flashback?
Everyone likes to point out Sr. Pink's change. He didn't used to look like a grown man in a baby's clothes. But Dellinger was a baby in the flashback. That was funny to me.
I love to [blah blah blah] watch anime, [blah blah], play video games, [blah blah blah blah blah]— Taz (@tazpause) July 12, 2015