Daishikkin Helena

Both stories feature a princess who is prisoner of war and repeatedly violated by the enemy, and both are filled with violence, gore, and sex. 

Both have open sex scenes, and both are based on rapes. 

Well the animation and art are very similar with the same kind of theme but with elfs instead.Plot is almost the same but instead of revenge it is based on avenge of a loved one.In the contence the difference is there is more violence and rape and has a mild flavour of romance (which darcrows does not have much of).Both are based in the middle ages and have a good chance they are based in europe.