Wise Mari swam on over from the Jade Forest and appears in the Celestial Tournament as one of the random Champions of Pandaria. This is the strategy I use to defeat him.
*This strategy was originally seen in this guide. I have never made any claims that I created this strategy.*
Pet and Ability Lineup:
Your Squad:
Any Moth. I used a Yellow Moth with Alpha Strike, Cocoon Strike, and Moth Dust. (Flying)
Mechanical Pandaren Dragonling with Breath, Thunderbolt, and Decoy. (Mechanical)
Any Aquatic Pet. I used a Yellow-Bellied Bullfrog with Water Jet, Healing Wave, and Frog Kiss. (Aquatic)
Enemy Team:
Carpe Diem – Grasp, Cleansing Rain, and Dreadful Breath. (Aquatic)
Spirus – Arcane Blast, Healing Wave, and Soul Ward. (Magic)
River – Dive, Pump, and Whirlpool. (Elemental)
The Action:
Open with your Moth opposite the Aquatic Carpe Diem. Cast Moth Dust. Carpe Diem will apply Cleansing Rain. Use Cocoon Strike to block his Dreadful Breath. Alpha Strike for 2 or 3 rounds, and Carpe Diem should be history. Wise Mari will bring out Spirus.
Switch to your Mechanical Pandaren Dragonling. In this particular battle, Spirus immediately put up Soul Ward, thereby negating any Breath attacks I could make. He will sometimes wait until his second turn to cast Soul Ward as well. Keep an eye on this ability; when he uses it, cast Thunderbolt. Thunderbolt will not damage Spirus with the Soul Ward up but it will both consume it and do damage to the backline pets. So in short, if he does not cast Soul Ward, use Breath. If he does, use Thunderbolt. After that, put up your Decoy and have him fruitlessly attack you for 2 rounds behind your wall. Resume Breath spam and Thunderbolt through Soul Wards. Use Breath until Spirus is dead.
Wise Mari will bring out River. River will cast Whirlpool and Dive. Resume casting Breath and Decoy on cooldown and continue damaging River until the Mechanical Pandaren Dragonling dies. Bring your Moth back onto the field; River should have very little health at this point. Cast Moth Dust and Alpha Strike at will and he should be defeated in a few rounds.
If for some reason RNG gets the better of you and kills your Moth, bring out your Aquatic pet to finish off River. Winner!
More Details:
Any Moth pet is suitable for the first slot in this encounter. All Moths have the three abilities needed to defeat this encounter; Alpha Strike, Cocoon Strike and Moth Dust. It really cannot get any simpler than this.
The Mechanical Pandaren Dragonling is a mechanical pet created by engineers of skill level 575; you can purchase it in the Auction House or craft one/have it crafted. The materials are not too expensive. The pet is learned as uncommon quality and only comes in Breed#5, or S/S. In this video, you will see I have opted to use a battle stone and upgrade him to rare quality. If you do have access to a battle stone I would definitely recommend that you consider this pet for an upgrade. It is quite unique in that it is a mechanical family pet with a Dragonkin attack; as you see in this video he does bonus damage to Magic type pets while at the same time taking decreased damage from them. This makes him an ideal choice against many magical opponents.
Any Aquatic pet will be able to perform in the third slot. The Mechanical Pandaren Dragonling and Moth usually are able to handle this fight flawlessly, but it is always good to prepare for disaster and have a strong pet ready to clean up in case of emergency.