For most of her life, Emma Frost thought only of her own needs and goals, seeing humanity as inferior to her own mutant race. She used her intelligence, charm, and telepathic powers to accumulate great wealth. Soon she joined the mysterious Hellfire Club, a group secretly dedicated to world domination. For years she helped that group gain the political and economic influence it desired, often clashing with the X-Men.Marvel Source
Over time, however, Emma came to see the teaching of young mutants as her true calling. Eventually she allied with Professor Charles Xavier and her former enemies, becoming a full-fledged member of the X-Men and a teacher at the Xavier School.
Further notes:
Artifacts: Idol of Khonshu (100% uptime from all of your dots, required) Advanced Metasensory Array (+1 and untyped 300+ is very nice) 2x Wildcard slot, use whatever melee/physical artifacts. ACoC WSJ Kung-fu AI Gok I don't care. My loadout is: GoK, ACoC, AI
Medal: Sabretooth (best because it's untyped DR and has some very nice defensive stats) or any melee/physical medal like Kurse, Tombstone or Grim Reaper. A 20%+ Magneto is worth having as well if you're having sustainability problems on longer fights. Blob is great for soloing as usual.
Legendary: M'kraan Crystal - I tested things out on the TC and the damage difference between Gungnir/Axe/M'kraan is like 2-4%. The crystal helps with sustain so we'll take that.
Runeword: RotS if you're still having spirit trouble, God of Mischief or Bowazon if you're not.
Costume: medkit + what you prefer: invulnerability, loh and health are good choices. CDR on costume.
Omega: Molecular Adjustment/Xerogenesis 10/10, then Human Augmentation/Reaver Program and Super Soldier Serum.
How to play:
After zoning (or dying) use Unlock Potential to get the Accuracy buff. Kick to get a bleed going. Drop Torment and inspire your minion. Diamond Heart. Start punching.
Diamond Form makes you very much not squishy, and it's a blast to play. Damage vise very competetive - sub 12 second dummy kill with a second person around.
Not that great for trash, but on bosses and raids you're awesome. Diamond Crush alone does upwards of 450k DPS self buffed.
Gear:
Slot 1: Cosmic w/ +8 to Diamond Crush and a damage roll (and +1 to Diamond tree, +8 to Inspire Minion/Spin Kick/Torment but that's like winning the lottery) OR +6 White Silk Gauntlets
Slot 2: Rebel's Black Bodice (backup: Nate Grey's or Amulet of Right)
Slot 3: Fred Dawson's Hot Dog Cart
Slot 4: +6 Diamond Tipped Stilettos
Slot 5: Cosmic w/ crit/cdr/hp/+5 to Diamond Crush.
Build from Shatterbird Marvel Heroes forums.