Phase II begins with many (20ish) Bash'ir Subprimal (elite)(12k hp) which spawn nearby. Things become somewhat hectic at this point. It did not appear that they all attack at once, but are either pulled or proximity aggroed.
After a short time, non-elite Disruptor Towers (70)(28k hp) surrounded by Bash'ir Controller (elite)(16k hp) spawn at a raged distance. The towers will fire AOE bombs on the NPC. Using ranged DPS on the towers will minimize the number of Bash'ir Controllers aggroed during this stage. As each tower is destroyed, the four Elites arround it will aggro on the NPC. Destroy the towers one at a time and be prepared for each group of Elites. Destruction of the Disruptor Towers will cause the Aether-Tech Adept Gem Vendor to be summoned and begins Phase III.
Shivan Assassin forms used: All 3 forms are used here. Fire Form for primary dps and cleansing Immolate and Shadow Vulnerability debuffs. Shadow Forms for Shadow Nova AoE killing all the Eye Stalks summoned, and keeping hp up. Ice Form only to Ice Block back Incinerate (Shartuul yell's "Prepare to be Incinerated!" and is a 10sec cast, long enough to pop Ice Form, and Ice Block, then switch back to Fire/Shadow forms)
Start this phase off in Shadow Form. Shartuul will periodically throw a large ball of energy to the top of the Transporter in the center, which breaks apart and lands to make a ton of Fel Eye Stalks spawn all over the arena. They do not move, but have a long range mind flay attack. This Mind Flay is shadow damage, and if you have the Shadow Vulnerability debuff on you prepare to get owned. All Fel Eye Stalks have low enough hp to die to 1 Shadow Nova, so if you stand in the center of a small grouping of Fel Eye Stalks in the South West corner of the arena, you can wipe them all with 1 Shadow Nova and keep yourself a safe place to stand/cast. Fel Eye Stalks also cannot be targeted for a second or two when summoned, so wait until they start actually Mind Flaying you to pop Shadow Nova. If Fel Eye Stalks are cleared out of the corner, you can now switch to Fire Form for primary DpS.
Shartuul's primary attack on you is a Shadow Volley that periodically causes you to get the Shadow Vulnerability debuff (much like a Warlock's Shadow Bolt crit). Also casts Immolate, and rarely casts Incinerate (VERY high damage, needs to be Ice Blocked back). Spam Flame Buffet and PyroBlast for your standard DpS, and watch your pet icon under your party screen for any debuff's. Immolate and Shadow Vulnerability are the 2 you're looking for, Flame Cleanse off immediately. Periodically Shartuul will pull you to him, then teleport somewhere else. Just run back to your safe corner and wait for him to walk back into range. There are 2 things that will make you leave Fire Form. First is Incinerate. If you see him yell "Prepare to be Incinerated!" switch to Ice Form at once, and Ice Block at the last second to bounce it back. If you don't, you'll take about 30% damage which is WAY too much to take from a single attack. Then switch back to Fire/Shadow. The Second thing is when he re-summons all the Fel Eye Stalks. Use that time to switch back to Shadow, Shadow Nova down Fel Eye Stalks, and consume any old Siphon Life's with Shadow Bolt, then re-apply new Siphon Life/Shadow Nova DoT's to Shartuul and switch out of Shadow Form. 90% of the fight will be spent in Fire Form spamming PyroBlast/Flame Buffet and Flame Cleanse to keep all debuff's off you. This is a LONG fight, sometimes more than 10-15min, so keep your rotation going. If you start to fall behind on HP (Or you just want to speed up the fight) Use the Chaos Strike(Special Attack) to get back into the game. Again, only cast Chaos Strike when you have 10 Flame Buffets, and an old Siphon Life on the target with your Siphon Life Cooldown up and ready. You can try to also work in Freezing your target with Frost Nova, but that's an extra step that while handy, and it does do alot of extra damage, isn't always needed. Sometimes you just need to get your life back quick. Chaos Strike for bonus damage from 10 Flame Buffets, then Shadow Bolt to consume the old Siphon Life, and re-apply a new Siphon Life and Shadow Nova to regen 220K hp every tick (like 10% of your life per tick). No matter how much you mess up, this trick will get you back to 100% HP, which should be enough to get you back in control of the fight.