Jarnys (Leanon)
That's the trigger, but there are deeper underlying causes. They don't get along because the Tryker and Zoraï ways of looking at life are nearly opposite. The Zoraï care more about their floaty philosophies and 'preserving balance' than about individual homin's lifes and happiness, like how they sacrifice their own to combat the Goo. Meanwhile the Tryker are hedonistic, frivolous, and superficial, they take lightly and even mock the worship of the Kami and the Zoraï philosophy and their shallow attitude erodes deep thought.And Tryker not liking the Zorai is because the Zorai kept the Trykers out of their cities when they were being hunted down in the old lands (I think it was during the beginning of the great swarm, but not sure)
Really, the Tryker and the Zoraï are more opposite than the Fyros and the Matis, the only reason the latter conflict is hotter is because the Fyros and the Matis are both more militarised races than the Tryker and Zoraï.