Dark Gate on stage 7
A Dark Gate, as the name indicates, is similar to regular gates, but completely dark in color.
The gate itself is a special type of monster who doesn't attack the player and can only be destroyed by the legions Blasphemy (bomb gates) and Hatred (power gates). This type of gate often guards hidden items such as Thanatos Chips, recovering items, experience gems, optimizing statues (--insert name here--) etc.