This novel is centered around the main character fighting alongside his companions. As for companions, most will consist of elementals, beasts, and creatures from legends, myths, and urban legends. I might throw in a Pokémon or two, maybe something from an anime, for all I know... (most likely not though) :P
Aside from summons, the main character will have friends that accompany him, albeit not all the time.
As for romance, the main character won't have a harem - it will be monogamy.
Forgot to mention, the system is going to be rather interactive with the main character. As the story develops, I plan on having the main character develop the abilities that he uses from the system on his own.