Taburou

Taburou's reason for wanting to commit suicide is his sighting of his doppelgänger across several months, a sign that's interpreted as someone's life is almost at an end. He wishes to die on his own terms.

[Spoiler] The first Taburou that appears is actually the doppelgänger. He explodes when the android Piitan stabs him with a cutter. [/Spoiler]

[Spoiler] When Piitan starts vomiting lots of mysterios jewels following their second suicide attempt, Taburou and Baracchi collect and sell as many of them as they can, leading a lavish life. [/Spoiler]