In Valkyrie Profile 2: Silmeria, there is an extensive Skills System, which can be equipped to enhance a character in various ways in battle. Skills are taught by linking a particular set of runes on a character at once that, when properly chained, teach a skill. Each combination (and Skill, for that matter) can be seen on the Equipment screen by pressing the (Triangle) button.
Skills are categorized into several different Types, each type revolving around particular mechanics in battle.
Rune Link: Blue Slash Rune, Lightning Rune, Strengthening Rune
Effect: "Makes attacks cause enemy to faint. Further attacks are more likely to break enemy guard."
Effect: "Increases the amount of purple gems that appear after an attack."
Effect: "Increases the amount your special attack gauge rises after an attack."