Phoenix Feathers
From God of War Wiki
In the God of War series, Kratos can find Phoenix Feathers by finding and opening hidden chests, or by searching in secret areas. For every six that he finds (every 5 in God of War: Chains of Olympus) his magic meter gets increased partially. After Kratos finds a total of 18 Phoenix Feathers (15 in God of War: Chains of Olympus), he won't be able to find anymore as his magic meter will be fully increased.
