>>718896624
What he
>>718897318 said.
The first build of RE4 was DMC1. You can even spot a few concepts, gameplay mechanics and models. For example, you can spot the dragon head of Alistor in the room where the dragons spew lava in RE4. The fatality anitions of RE4 came from DMC1, which is the only game in the franchise that does it.
Haunting Ground was made from assets of the other RE4 builds and based on the castle build. It's technically a Clocktower game.
The other one is actually RE4 itself. These 3 games became part of an unofficial trilogy because of this connection. From what I understand, Capcom was a lot smaller back then and the same people worked on a lot of the same projects. If you look through the list of staff in these 3 games a lot of them overlap.