... Pleading the fifth? I'm not sure, but judging by the
Ace Attorney games, it's related to "the right to not testify if it can incriminate the witness"... I think.
What I do know, however, is that it's different on Seretou

Seretou's "fifth pleading" equals to "the right to eat as much as you can during a trial".

Seretouan law is weird and corrupted.
... And exists solely for the purpose of being weird and corrupt.
... Speaking of which, I dreamt that there was an invasion of ninjas called "Seretouans" and that they tried to take over the world... using shuriken. And then they caught fire after they were given a glare.
... Urk. Not a normal dream... ¬¬