Seiya Ryuuguuin

Seiya Ryuuguuin (竜宮院 聖哉, Ryūgūin Seiya) is the protagonist of Cautious Hero and one of the brief characters of Isekai Quartet, alongside Ristarte.

Personality
He is a very cautious person, even so by normal standards, not wanting to join the school festival due to the unknown dangers it may have despite it having no red flags.

Plot
Seiya and Ristarte were at the school's entrance during the school festival, but due to Seiya's overly cautious nature, he ended up leaving as Ristarte grabbed unto his leg in protest.

Abilities and Powers
Similar to Reinhart, Seiya has several powers that make him unbelievably powerful and nearly impossible to beat.