Call to Greatness spell was added in Book 11. That and lack of description (see here, "You call out to a fellow, inspiring him to greatness.") is making it one from well forgotten spells. Yet, it is very usefull, especially in end-game encounters.  Effects (please correct/add if i haven't got it complete) are as follows :

• Champion : Defeat response, 2 Fervour every 5 seconds
• Guardian : +25% Threat
• Lore-master : Blinding Flash refresh every 5 seconds
• Minstrel : +10% Healing, Chord of Salvation reset every 5 seconds
• Hunter : -15% Threat, 1 Focus every 5 secs
• Captain : Defeat response every 5 secs
• Burglar : +15 damage to positional attack

The resetting timer every 5 seconds (usually for 15 seconds

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