Relevant Talents used:

Mindbender
Twist of Fate
Cascade

iLvl: 684

This boss is dealt with using the same conventional strategy.

Farraki Tribe phase:
The adds are not too difficult. Basically you can dot them up and ignore. The wastewalkers have quite a bit of health though so they may require an occasional Mindblast. Although adds should be prioritized, all the heavy nukes (Devouring Plague, Mindbender and Mind Blast) should be reserved for the boss. Kill Dinomancer ASAP when it appears and click the orb to trigger the end of the Farraki phase. Once Horridon is stunned, aim to DPS him down as much as possible.

Gurubashi phase:
Similar to Farraki phase, adds should be prioritized. Again, the heavy nukes should be reserved for the boss. Aim to get the boss down to below 30% to activate Wargod Jalak after clicking the orb dropped by the Dinomancer. Doing so not only means there are fewer adds remaining, but the boss itself is also stunned at the same time, allowing you to cleanly engage and defeat Jalak without too much interruption.

Once Jalak is down, Horridon will deal increased damage, but at this point it will not have much health remaining so it's best to simply burn it while ignoring the next (Drakkari) tribe of adds.

The conventional method is to wait till all 4 tribes are defeated before getting the boss down to 30%. However, personally I would aim to get the boss down to below 30% and kill Jalak before the Drakkari adds spawn (as they are extremely annoying adds).