What's the most "mature" Nintendo-developed game?

[GooseGaws]

@RolStoppable:

The Fire Emblem series definitely fits in with what I'm talking about, as mentioned in the first post. Not only do you have the lives of your soldiers to worry about, there are innocents to be protected from war criminals and bandits alike. This series has also been the most consistent in theme and style out of all of Nintendo's series, but that also relates directly to the genre and subject matter. It's not unexpected for the Fire Emblem games to be this way, as they always have been. Though, I suppose it is significant that they have remained as such for so long.

The Advance Wars series looks like it will be experimenting with a new, more "mature" style in the next installment, so it will be interesting to see where that goes. Both series are developed by Intelligent Systems, which was born from Gunpei Yokoi's R&D1 studio which created the Metroid series. They seem to have the corner on serious content within Nintendo's internal teams (though they are also responsible for the whimsical Paper Mario series).