Summon the enemies you kill to solve puzzles, including a horse, a tree, a miner and a dragon. Some areas are unreachable without the right summon so you must find out how to get one it to advance to the next area. some can get places you cant, some you can ride to enhance mobility and some can defeat enemies you cant. If a summon kills an enemy, it wont drop its soul so you have to find a way to kill it yourself if you want to summon it. some enemies you cant defeat and just have to find a way to get past.