Devil Lore (3.5e Spell Mechanic)
From D&D Wiki
All spells with the "Devil Lore" descriptor have the following effect when cast:
All active Devil Lore spells on the caster have their duration extended by one round during a round in which a Devil Lore spell is cast. They cannot be extended by more than one round each round in this way.
Devil Lore Spells By Level