In the GURPS 4e Sorcery system, spells are created by using the Sorcery spell-creation rules in the "GURPS Thaumatology: Sorcery" supplement. To create a spell that resembles "Lumos" from the Harry Potter universe, which produces light at the tip of the caster's wand, we would build a spell using the appropriate modifiers to create a sustained, bright light. Here's how you might create the "Lumos" spell in GURPS 4e Sorcery: **Spell Name:** Lumos **Base Spell:** Create Fire (as a starting point for creating a visual effect like light) **Power Modifier:** Sorcery (-10%) **Spell Effects:** Innate Attack (Light) Spell Description: "Lumos" creates a bright, steady light at the tip of the caster's wand or finger, illuminating the area like a torch. **Base Cost:** The base cost for a Create Fire spell is 5 points/level from the "Gurps Basic Set: Campaigns" but since we only want light, not heat or fire damage, we'll reduce the base cost. Let's say the GM agrees to a base cost of 2 points/level since it's purely illuminating. **Modifications:** - No Heat/Damage (-80%): Since "Lumos" only creates light, not fire, we apply a large reduction in cost. - Cosmic (No die roll required, +50%): "Lumos" reliably produces light without a need for a success roll. - Area Effect (+50%/level): To simulate the light illuminating an area rather than just the caster, apply an area effect. A 2-yard radius (level 1) might suffice, costing +50%. **Final Spell Cost Calculation:** Base Cost (2) - Modifiers (80% reduction for no heat/damage, +50% for Cosmic, +50% for Area Effect) = 2 - (2 * 0.80) + (2 * 0.50) + (2 * 0.50) = 0.4 + 1 + 1 = 2.4 points/level. (Round up or down per your GM's preference; we'll round to 2 for simplicity) Therefore, the "Lumos" spell would cost 2 points for a 1-level spell that creates a bright, torch-like light in a 2-yard radius around the tip of the caster's wand or finger, with no roll required. **Casting Time and Duration:** For a spell like "Lumos," GURPS Sorcery generally assumes a standard casting time of one second, and the duration might be something you want to maintain through concentration. You could apply modifiers for Increased Duration (like +20%/level for Maintained Duration) or use the Reduced Time modifier if you want it to light up instantly. Here's how the final spell might look in a GURPS character's spell list: **Lumos (2):** Innate Attack (Light, Area Effect 2 yards, No Die Roll Required) [2 points] The character can now cast "Lumos" with the confidence that it will produce a bright light whenever needed, following the Sorcerous rules for energy costs and potential magical fatigue.