The temple guardian in "Romantic SaGa 2: Revenge of the Seven Heroes" is the first BOSS that players encounter in the Erunep Temple. If you want to fight this BOSS, you can stun him. In addition, he Does not have any elemental weaknesses, but has weaknesses to greatswords, maces, and martial arts.
How to defeat the Temple Guardian of Revenge of Seven Heroes in Romancing SaGa 2
Guardians resist all status effects except stun. Therefore, the only way to affect his turn is to stun him. Additionally, he has no elemental weaknesses, but has weaknesses to greatswords, maces, and martial arts. Since his attack power is extremely powerful, I recommend bringing a heavily armored character and using the Imperial Cross formation (with the heavily armored character first, of course).
Additionally, for a character who uses a staff/macale/hammer, having the "Bone Break" skill is very useful as it reduces his damage output. Add in "Water Dance" to buff your heavily armored characters, and they'll be ready to go. From that point on, keep your team's health up (especially the characters in front), use this skill again when the "Bone Break" effect wears off to weaken the Guardian's attacks, and eventually you'll be able to defeat him.
While you can use a few different units as shields, the heavy infantry's ability to auto-block really makes them a strong choice.