Hero Temple is where the heroes coming after Him, the great hero Heracles, presents their respect to Him, and communicate with each other. The Temple increases the experiences gained by your hero, also allows you to preserve a certain amount of experiences from your fallen hero after your hero's death, so that the new hero taking his/her place would inherit his/her will. By upgrading your Hero Temple, you can receive more experiences bonus, also keep more experiences for your new hero.