Rich
If you asked the mortals, Persephone, or even Hermes, they'd tell you Mr. Hades had always been rich. It was easy to see why; for as long as they'd known him, he was king of all that glittered underground, king of all the riches mortals were so eager to dig up.
But in his earliest days, it wasn't always that way.
Only his brothers knew that Hades had started out anything but rich, and by choice. When his father's inheritance was split between them, all blood money and lies, Hades declared he wanted nothing to do with Cronus' fortune. He'd forge his own path, and Zeus and Poseidon agreed; it meant more for them.
So while his brothers spent their money on women and wine, on horses, boats, and other status symbols, Hades rolled up his sleeves and got to work. He made his money the old-fashioned way, and by the time Hermes came by, his wealth far eclipsed anyone else's.
Now they all knew him as Mr. Hades, the Rich One, God of Wealth, and that was how it would stay in the minds of gods and men.