Your search for "Luminous Spark MRL-100" revealed the following:
Luminous Spark - MRL-100 - Common - 1st Edition from Magic Ruler 1st Edition, available at 401 Games Canada. Rarity: Common Card Text:Increases the ATK of all LIGHT monsters by 500 points and decreases their DEF by 400 points.
Luminous Spark - MRL-100 - Common - Unlimited from Magic Ruler Unlimited, available at 401 Games Canada. Rarity: Common Card Text:Increases the ATK of all LIGHT monsters by 500 points and decreases their DEF by 400 points.
Luminous Spark - SRL-100 - Common - Unlimited from Spell Ruler Unlimited, available at 401 Games Canada. Rarity: Common Card Text:All LIGHT monsters gain 500 ATK and lose 400 DEF.