Seeker Zusshi is the Townlong Steppes Grand Master, and can be found under his tree near the lake at 36,52. His team consists of Diamond, Mollus and Skimmer. I use the same team for Zusshi and Shu, so your team here is: Seapony, Raven, and kunlai Runt. This is a switch team, depending on RNG (random number generators - AKA LUCK) but this is the fast version.
Diamond is elemental, so we start with our elemental killer, Sea Pony. I also like crabs and the Magical craw dad, but the pony is all agro, and hits hard. start off with whirlpool, get it ticking. hes gonna use frost shock and nova, not a problem. use water jet, then surge. Surge always goes first and the whirlpool should resolve leaving him at little health.
Mollus is a critter, so here Id just stay with Seapony, hit whirlpool and surge to keep whittling him down, and when dive resolves and kills him, flip into the kunlai runt. Runts rampage will RAPE out little snail buddy, and its night night snail.
Skimmer is aquatic, which you all know by now means " please lord, just kill me" Just hold the runt untill his pump resolves and kills it, or flip to the raven and switch his rain to darkness, and nocturnal strike with alpha strike spam and its good game. LOL@AQUATICS! Watch the video below for a one shot!