A group in my guild has Caverns of Time: Black Morass (Dark Portal) on farm status. This section is to show other hunters how to solo control adds.
I have S1 head, shoulders, gloves, and legs. My weapon is Sonic Spear with Savagery. My bow is Melmorta's Twilight Longbow and chest is Laughing Skull Battle-Harness which both drop in this instance. The rest of my gear is pre-Kara instance drops or quest rewards. I am a BM hunter with points in MM and SM for higher crit chance and higher health.
Have food and drink available to use fast, preferably Mage Enriched Manna Biscuits. If you are low on health/mana between the fights you will need to eat fast so bring plenty.
It is best to use a high DPS pet on this run because you want these things dead asap.
This instance is a series of 18 fights. You will have waves 1-5 then a boss (set 1) , 7-11 then another boss (set 2), 13-17 and then the final boss (set 3). Your job is to protect Medivh from the adds that spawn. Medivh has a shield that is protecting him and as the adds get to him the shield starts to fail. If you can keep all the adds off of him you are gaining time for your party in case there is a wipe or to mana/health up before the final fight.
When you enter the zone there will be many animal mobs around. An easy way to get through them is to turn on track beasts, mount up, and pull 3-7 mobs to your party, numbers depending on how many AoE classes you have and party strength. Clear a path straight south until you see a glowing purple orb. This is where Medivh is. Do not get too close to him or you will start the event. Once you are to the south you want to clear the islands in a semi-circle around Medivh. This is the area the portals will form and dragonkin will spawn from them. When rounding up mobs only get within 5-10 feet of them or you will have a high chance of them dismounting you.
Once the area is cleared and everyone is ready someone will run up close to Medivh and the event will start. Scan around and see where the portal is opening. Have your pet on defensive and growl turned on. You want to stay around the water/land that is close to Medivh because this will give you clear view of anything coming out of the portal and keep your pet out of the AoE area of the mob the rest of your party is on. If you get too close and your pet gets argo on the main mob put your pet on passive, back up, and put it back on defensive when it is near you.
The types of adds are different in each set of waves. In set 1 you will have 1 Assassin, 3 Whelps, 1 Chronomancer. The Assassin should be Concussion shot, Serpent Sting, then if you are a BM hunter use your pets Intimidation to get the argo off of you. Be warned the can Kidney Shot you. Then stand back and range him to death. With the 3 Whelps I Multishot them to me and lay an explosive trap (the AoE one) and let my pet/my melee kill them. Controling the whelps is the only time I use a trap. With the Chronomancer it is a caster. Shoot it once it is outside of the main mobs AoE range so you can send your pet in without worrying about your pet getting argo on the main mob. Just range this one to death. This one can slow your movement down with its freeze spell.
When you finish on one portal scan around for the next portal and when you get to the area between it and Medivh sit down and eat if you need to. Wait until your tank gets argo or your add gets out of the main mobs argo range before you pull the first spawning adds.
On set 2 the adds will be 1 Executioner, 1 Chronomancer, 3 Whelps, 1 Assassin. Do the same as before but with the Executioner know that it can Hamstring you. Below is a video i made of the second set. It didnt upload to YouTube very well but I am looking into other upload sources to maintain better quality. Direct link to video.
Once you make it through the first 2 waves you are pretty much home free. During this last set of mobs your party will set down the chrono-beacons one at a time for the last 5 mobs before the last boss. Our group usually goes alphabetically so everyone knows when to place theirs. Put an icon of the beacon on your hotbar and when it is time to place it right click the icon and you will get a green pattern on the ground like when doing Volley. If the dragon helper is places in the right spot each time you will have next to no add this bout. I keep my pet back if the dragon helper is placed in an odd place and shoot at the main mob and look around for any adds that come through. If the dragon helper is placed right in front of the portal I send my pet in on the main mob and range and adds I see.
If you have kept all the adds from coming to Medivh then his shield will still be at 100%. When the last boss comes out and goes for the shield your party will have some time to mana/health up before the fight. If you have the Hawk Eye talent you can stand out of range of the dragons AoE proc that stuns you. Being this far back though means you probably wont be in range to use the Kill Command. When the dragons feet turn red hit it with Tranquilizing Shot and that will remove the fury effect. Below is a video of what to expect for the last set of mobs. Direct link to video.