Euma Siarath, the king of Euchrisse in Eiyuden Chronicle: Hundred Heroes, trusts army chief Kassius to the point of allowing him to make decisions on his behalf. So when he decides to join Nowa's team in support of the Alliance, it means all of Euchrisse is in support too.
As you progress the story and get to The Meeting of Kings in Athrabalt, Kassius will automatically be recruited to the team.
Role: Support
Support Skill: Euchrisse Cavalry Charge - Euchrissian cavalry is called in to charge, damaging all enemies.