Minotaur Horns are collectable items from similar to Phoenix Feathers and Gorgon Eyes.
God of War Series
Ghost of Sparta
The Fire Meter can be upgraded once every time 5 Minotaur Horns are collected.
A player can encounter a glitch in the game if it was finished for the first time. The last 5 Minotaur Horns won't be saved. And the only way of fixing this is by replaying the game and collecting the last Minotaur Horns. This can be due to the Fire Meter not fitting correctly in the HUD.
God of War III
There is 12 present in the game with each 3rd adding further to the item bar.