In Exalted, everyone has a trait called "Compassion". People with high compassion are compassionate, caring. Solar exalted, those with the most extremes related to virtues, may snap and undergo the Limit Break "Red Rage of Compassion". It's angrier than the Limit Break "Berserk Anger".
In Magic: The Gathering, the color blue works like this. It usually starts slow, but if it makes it to mid-game, your opponent is in VERY dire straits as he begins seeing his spells coming out wrong, his cards being discarded, his creatures taken control of, and his entire game plan obliterated.
There's also White, the colour of Law and Order, of healing and protection. And of 'Wrath Of God' and 'Day of Judgement', which are the magical equivalents to a scorched-earth policy against anyone stupid enough to be a credible threat....
Of course, if you want a literal scorched-earth policy in white, there's always Armageddon - "Destroy all lands." See, white is all about equality—that is, destroying all of its own things and all of yours, no matter how many "all" was for you and how many "all" was for it.
Gennifer Weathermay-Foxgrove, from the Arthaus Ravenloft product line, is the more ladylike, gracious, refined, and patient of the W-F twins. She also has a kickass Berserk Button moment in Van Richten's Guide To The Mists, not to mention she's probably an unwitting werewolf.
The Children of Gaia are the gentlest tribe in Werewolf The Apocalypse - but holding in that Rage all the time makes it that much worse when they finally lose it.
Demon The Fallen has traces of this as well. The Fallen were Angels once, after all, with all the inherent goodness that usually implies. Even before the Abyss turned them into Complete Monsters, the Fall and the War of Wrath made even the gentlest among them into engines of destruction.
In the Warhammer 40,000 fluff, the Salamanders, Ultramarine, Space Wolf, Blood Angel and Raven Guard chapters of Space Marines are reknown for actually giving two-flips about civilians and their safety, and will ensure to avoid inflicting "collateral damage" unless they genuinely have no other choice. They are, in turn, hulking armies of nine foot tallFlame enthusiasts, Space Romans, Space Vikings and Space Psychos, respectively, who can and will ruin your day with all sorts of mayhem if you piss them off.
Oh, come on. Better than some of the other Chapters maybe, in that they actually notice and care about humans, but the Astartes are in no way nice. If they get the slightest inkling you're in any way slightly an enemy, even the more benevolent ones will swiftly and brutally murder you and anyone who looks like you. They have no art, culture, hobbies, friends (in the normal sense), loved ones or mercy, and they exist only to fight and kill. They are not nice by any definition.
The Salamanders do have "loved ones, art, culture and hobbies.". They have loved ones (they still keep ties with their families on Nocturne, darn near unique among the canon Space Marine chapters), and they are all quite handily proficient as artisans and craftsmen, which qualifies for "art, culture and hobbies." Whether they satisfy the textbook definition if "nice" is really a YMMV to be sure, though.
Blood Angels actually paint, and seek artistry as a form to express themselves, such was Sanguinius view of life that a Blood Angel should always seek self improvement. Which is one of the core beliefs of the chapter, to bring a better life to mankind.
Some members of the Ultramarines Second Company actually befriended the rest of the human forces of Damnos. Though they do not keep contact with them, those families that have one member inside the Ultramarines chapter actually are elevated in status.
Space Wolves almost entered in an outright war with the Administratum for theirs actions after the First War of Armaggedon, where they decided to kill the entire human population of the planet because they fought AGAINST the demons. Not only that, but Logan Grimnar launches from time to time, relief crusades, that seek to protect Imperium citizens from the Imperium itself.
And in the 40K universe, "nice" is not being a complete prick.
