Act 6.2.5 is the hardest chapter you will find in Act 6.2 (of course 6.2.6 is hard, but it’s Tha Champion Boss only).
Challenges You Will Face While Fighting Mordo Boss in Act 6.2.6
Special Delivery: You get 15 Combo Charges and each hit removes 1 charge. Launching a Special Attack will restore them. If all combo is removed, you degenerate equal to 100% of the Defender’s Attack Rating over 4 Seconds.
Hurt Locker: You cannot use the same type of special attack twice in a row. If you do so, you get a delayed blast charge for 5 seconds. Using a heavy will remove that blast charge, but if you fail to do so, you take 50% of your health as direct damage.
Hurt Locker with Special Delivery is the word combination that forces you to use a champion that gains power or a champion that can kill without a hit (that is only Quake).
Spite: If your champion gains a buff, Mordo will fill his power bar by 18%.
Strength in Number: Attacker gets 25% reduced ability accuracy for each knocked out champs. (That means: 4 knocked champions = 100% reduction in ability accuracy = you cannot do anything, not even damage)
Top Counters to Fight Mordo in Act 6.2.5
Note: If more than 1 champion is already knocked out in your team, it’s better you use a team revive to avoid ability accuracy reduction.
Symbiote Supreme can gain power without any hit. Use the Mystic Dispersion(MD) mastery to get the most of it. He can nullify buffs and do some great damage.
We all know Quake is a Mordo Killer as she doesn’t really need to hit to do damage.
Doctor Doom (Duped)
Combine Medium + Light + Heavy combo to apply stagger debuff. When Mordo gets power gain, it will be nullified and Doctor Doom will get that power gain buff instead. So he can use lots of special attacks during a fight. He can also steal Power using L1. It should be an easy fight.
Ghost Hits hard enough to finish a fight quickly. A duped Ghost gains some power every time an opponent misses an attack. So it makes the fight easy.
Wasp makes it a lot easier to use Heavy attacks that cannot be interrupted. So Wasp can use a lot of heavy attacks to fill power bars with lesser hits.
You will have to rely on heavy many times to keep alternating between Special 1 and Special 2. The heavy attack gives more power and sometimes, you will have to take some block damage to get enough power to use special. But, Void can stop the power gain permanently to help you fight easily.
Iron Man Infinity War (Duped)
Keep him below or at 15% health. He can bypass astral evade. At or below 15% health he gains power whenever he armors up. Keep using Special 1 and Special 3 that will also control the power.
Blade Danger Sense helps a lot here. Here is a video for a demo. Make sure all team members are alive, else it’s not gonna work for sure.