Twin Furies

This guide is for people new to bossing, or those needing a refresher. If you are a PvM maniac, and know the fight, there's no need to read ahead.

Recommended Gear
The boss has no weakness, however melee is preferred, since the two boss monsters group up and share health.
Armor - Malevolent<Torva<Anima Core<Tetsu<Bandos
Neck - Amulet of Souls<Reaper Necklace<Brawlers Blood Necklace<Saradomin Whisper<Amulet of Fury
Cape - Comp Cape<TokHaar-Kal<Max Cape<Fire Cape<99 Cape
Weapon(2h) - Scythe<Dragonrider Lance<Attuned Crystal Halberd<Chaotic Maul
Weapon(2x1h)- Drygore<Tetsu<Blade of Avaryss/Nymora<Chaotics
Ring - Asylum Doctor (w/ Ring of Vigor switch)<Ring of Death<Warrior Ring(i)<6th Age Circuit<Berzerker Ring
Aura - Berzerker Aura<Vamp Aura<Brawler Aura<Ancestor Spirits Aura<Dark Magic Aura<Inspiration Aura
Pocket - Illuminated God Book<Scrimshaw of Attack<Scrimshaw of Vampyrism<Attacker's Insignia<Sign of Life/Death
Inventory - This varies depending on how you attack, and the gear you bring, but I recommend bringing a few (4-6) of the highest stat boosting potions you can make/buy, Prayer restoration potions (Super Restorations work too), a Beast of Burden familiar, and fill the rest of your inventory with food.

Getting There
The fastest way to get to The Heart is by breaking a teletab, which can be bought on the G.E. and used after completing the Tales of the God Wars miniquest.
Next is by using the Desert Amulet 2 to teleport to Nardah, then running south.
Teleport to the fairy ring using code D•L•Q, then running south.
Taking the magic carpet south of Shantay Pass, at the south end of Al Kharid, to Pollivneach, running south to the next magic carpet, taking that to Nardah, then running south.
Once here enter the dungeon.

Upon arriving, you will need a 40 kill count to enter the instance (20 you have max reputation with the correct faction). Unlike GWD1, The Heart has a multiplier when killing members of Zamorak's faction, which increases by .1 with each kill, until 3x is reached (4x if a Shard of Mah is equipped), which means that 1 kill = +3(4) kill count, and the KC stays indefinitely, until they're used. Zamorak's faction is located in the north-west corner.

The Fight
There are a few mechanics and things to watch out for during this fight.
The twins will start in the center of the room, where you'll want to turn on your prayers/curses (Protect from Range or Melee/ SS + Turmoil) and use stat boosting potions.
There, Avaryss will jump on the wall and fly to the opposite wall, smashing anybody in a 3x3 area in front of the attack. This should be avoided, and will be very easy to walk out of it's path, if you turn your camera to find her on the wall, getting ready for the next attack. After this happens 4 times, she will fly to melee attack you.
After a few auto attacks from the twins, their next attack is when Nymora flies to a 4x4 location in the fight, and begins pounding the ceiling, dropping stalactites. At this point, she becomes unattackable. Your goal is to stand directly underneath her and dps Avaryss, avoiding the damage done by the falling rocks. After a few seconds, she will fly back down and recommence attacking you.
After a few more auto attacks, the twins will fly to the center, and begin channeling a fire bomb. At this point, a timer bar will appear over both their heads, counting down to the explosion. The edges of the fight will become engulfed in flames, so avoid standing on the outer edge. During this phase, the twins will take 2x damage, and will be close enough to both be hit by 1 hurricane/earthquake (if using a scythe/lance/halberd) or, if you have 100% adrenaline, it's recommended to use Berzerk to further increase damage done. Once the timer gets close to reaching the end, run towards the edge of the map (where the flames I recommended avoiding earlier are. Don't worry, they'll disappear quickly) to avoid the massive explosion, and avoid getting killed.
Then it's rinse and repeat.

If you have any further questions, feel free to pm me in game, or respond to this post.

Happy 'Scaping!