Disgaea is a Turn-Based Strategy-RPG franchise by Nippon Ichi Software (NIS) of Japan, and has been running since the early days of the PS2. The series and its spin-offs are well known for deep customization, not only through the myriad characters you can collect, create, and level up to 9999 (many times over if you wish), but for the weapons and armor you can mix and match. Not only that but in the Disgaea series you can delve into the Item World; A series of randomly generated dungeons within items. As you level an item and populate it with specialists (stat boosting monsters) it can become immensely strong and enable you to face even the most fierce foes in the series.
Even if you don't care to plumb too deep into the customization mechanics of the games, or the post-game content, you can still enjoy the over-the-top plots, filled with zany characters ranging from a love-obsessed angelic assassin, to a perverted floating frog-thing, and even a demon turned talking book.
You choose for yourself how you prefer to play. You can choose for your characters be a death-dealers that rely more on crushing offensive prowess, or a nigh indestructible long game player, a mage specializing in various elements, status inflicting tactical ninja, ranged attacker, or any number of other things. Each game offers a wide variety of playable characters to fit any play style.