Fight fire with fire! Or more precisely: Protect yourself with flames from the inferno. The Fire Sealing Rune contains the power of the fire elemental itself, creating a shield out of blazing flames. No fire elemental attacks or magic of that kind can break through, making the wielder invulnerable against that element. The downside of this rune is its liability to water, which will engulf the flame shield, resulting in painful attacks. But keep in mind that fire is the more commonly used element compared to water, even by enemies. Normally, the water damage inflicted to the bearer of this rune will be doubled, with the exception that Suikoden V subtracts one level from the water resistance, which is actually less excruciating.
Without a doubt, the Fire Sealing Rune works greatly during the events of Suikoden III. Here, area spells of the fire elemental runes tend to hit your own members quite often, and this is the key to prevent them from taking damage. Watch out for the crystal dropped by the Troll Dragons. You may want to keep a few of them for later usage.
Suikoden V introduces its counterpart, the Water Sealing Rune, for the first time. - Celes