Achilles: Legends Untold

Throughout the game you'll find tombstones where you can use a set of items to lay a soldier's soul to rest, granting an extra skill point. The items will generally be a drop from the surrounding enemies, or a glowing collectible in a nearby location. These will be marked as "Alters" on the map, and will disappear from the map once you have used them. The locations and required items are as follows:

Greece

I got all of the items above with no farming except the Pure Essence of Blood which I had to farm from the six lions next to the Dead River shrine, and Pure Essence of Light I only needed two more and got those from the soldiers at the Harbor shrine area.