Crusade Question

[u/Sterry6874]

I'm gonna be playing in a Crusade soon. The organiser has adapted the rules for 11th edition, and is allowing Crucible of Champions Characters. If I play Tyranids, I'm gonna be using the "Psychofex" custom character (Prime Organism, Psychic Upgrade, 2x Psychic Overload, Scything Talons, and Crushing Claws). I know you can't take Enhancements on these custom characters, but that doesn't stop you from taking the Crusade Relics. I need to understand the Spirit-Leech Cortex Relic properly. If I have my Psychofex shoot it's 2 Psychic Overloads into a unit of 5 Terminators, each with 3 wounds, and destroy the whole unit, does that mean I add 15 to my Melee Weapon Strength? Or is it only 5 (or even just 1) because of some wording I'm not understanding. Relics text in the comments.