I can't agree with you at all, Februs x)

DRK do not learn by themselves : Sid and Fray had a master they adored and respected, and he taught them everything he knew. In a similar way, Sid is a teacher for us, although he's himself pretty confused for a while... Mogs, finally, are our masters, and tell us about the power of Love to dominate Darkness. DRK are no more selfish than PLD, but they do have some bitter pieces of mind. For example, they are given some aptitudes like Sole Survivor, that grant'em more power when they resent hate or the joy of killing... When they are passionated, in fact. But the thing is : their skills are linked to sadness, hate, and their power is governed by love. The most powerful passions.

In fact, they are tanks, not because they have to, but because they want to protect their friends.

And PLD do work together... but in the end, as I said, they devour each other's power. It's clearly said, several times : when you eat the light of a PLD's crystal, it needs to be rebuilt over time, the loser loses his power. And the ultimate sword of PLDs reacts to the PLD that earned the most light. However I look at it, it seems pretty dark... Yes, PLD are group tanks, but because they have to, or so it seems... Maybe it's because of friendship, but they seem to get rid of friendship pretty easily...