Grand Master Shu

Wastewalkwer Shu's pets are as follows:
Pounder - Level 25 Rare Elemental
Crusher - Level 25 Rare Aquatic
Mutilator - Level 25 Rare Beast

Mutilator goes last.

Took me a lot of trial and error to figure out a two-pet team for this guy so I could include my Elekk Plushie. Most of the suggested teams in guides/comments I found included a pet I didn't have leveled quite yet.

What I ended up going with was Anubisath Idol [Demolish, Sandstorm, Deflection] and Eternal Strider [Pump, Cleansing Rain]. My Strider is P/S rare but I'm not sure it matters much.

Use Sandstorm whenever off cooldown, Deflection to block Whirlpool and Demolish as filler. It takes a bit of time to kill Crusher [about 3 Whirlpools], but you shouldn't take too much damage if you time Deflection right.

I stayed with the Idol until after Pounder cast Sandstorm, then switched to the Strider. Cast Cleansing Rain to change the weather back [and whenever on cooldown to help heal your Idol in backline] then Pump until Pounder is dead.

When Mutilator comes into the fight, keep using Pump until your Strider dies. Switch back to Idol and Demolish until win!

Hope this helps someone who had the same problem I did!

And Crusher goes first