Incubation can only be used if you have Grade 10 Purple Grade Heroes (Yuna/Godly Gabrielle/War Goddess Minerva/ Fallen GodLucifer) or Grade 11 SS Gold Heroes (Hela/Bahamut/Odin/Belandry).
*You get another free incubation slot for being married. Must be VIP and spend gems to unlock extra slots.
By matching up your Hero with your friend’s Hero, you can incubate an Egg and have the chance of getting a specific Guardian Spirit depending on your Hero type and their Hero type match-up.
Guardian Spirits have specific attributes to add in Hero Protection to increase certain attributes. The higher the grade, the higher chances of getting additional increase on other attributes. They are separated between Light Guardian and Darkness Guardian. Once bar reaches 100% players will have to use Dragon Teeth to breakthrough.