4 of several ways:
- the material of the weapon itself is replaced by one with e.g. glowing (emitting colour) rune letters
- the outline of the weapon is a low-poly mesh with invisible material just the glowing edge line is visible
- you can add several smaller lights (0 light source radius) attached to the weapon for a general glow and also light-effect on other objects
- the 3 particles/swarms are emitters, check out cascade sci-fi effects or magic effects.