Song: 亡き王女の為のセプテット Acoustic arrange - Silver Forest
Recorded via Fraps@60FPS

Not an overly difficult boss

The differences between Normal and Heroic:

In Heroic Titan Gas will be active for the entire fight (Deals 1800~ Damage every second and increases all units melee damage by 50%).

The biggest change to this fight is whenever a construct is killed it spawns a Titan Spark. Titan sparks will fixate on a player and will explode either on contact or when killed, this deals 90,000 Damage, can be reduced via feint, or simply just kill it with Shuriken Toss. Furthermore, any construct within 8 yards of the explosion will have their attack speed increased by 50% for 2 minutes. This effect stacks.

Another change, that actually is responsible for this fight being relatively easy is the change to Devastating Combo. Devastating Combo is a chain of 10 attacks (5 on norm) that both bosses will do, avoiding all of the attacks (not really possible or needed) grants you the special action Opportunistic Strike for 3 seconds (Deals 120k damage).

Respec Shuriken toss, it helps for Phase 1.

Glyph for 15 second Evasion, helps immensely for Phase 2.

Phase 1 - Easy phase.

There are 3 types of adds that spawn throughout this phase.
Emperor's Rage - Basic HP add just kill it.
Emperor's Strength - Medium HP add, dont stand in the stun circle.
Emperor's Courage - Annoying add, Shuriken Toss to kill it (Yellow damage from ST goes through the shield)

After an add dies it spawns a Titan Spark, kill it with Shuriken Toss and you dont have to worry about the damage, yet.

Once 90 seconds has elapsed both Jan-xi and Qin-xi will engage. Quickly kill off any sparks that are left (if any) and then blow all DPS CDs and Combat readiness since this is where they will hit their weakest allowing you to stack it.

Adds are going to contine to spawn during this phase meaning that sparks will also be spawning due to Blade Flurry. Try to avoid the Titan spark explosions.

The most damage that is going to happen during this phase is between Qin and Yan's Devastating Combo attacks because for each Combo that hits you your armor is reduced by 10% lasting 2 minutes. Furthermore each Titan Spark that dies near the constructs will increase their Attack Speed by 50% lasting 2 minutes and stacking. Save Evasion for these moments.

How I handled phase 2 Defensive CDs

Beginning of the Phase w/ 0 stacks of Reduced Armor and 0 Stacks of Energy of Creation (Attack Speed buff) - Pop Combat readiness when both are within melee range of you.

After First Devestating Combo pop first Evasion, pop second Evasion right before the first wears off (You will need to or else you'll die due to their incredibly fast swing timer).