Knight in the Nightmare - Story Plot

[exquisity]

Hello! Years ago I played halfway and stopped; just managed to complete it. Can anyone please kindly explain the story plot PLEASE? I'm really very confused - it's like back and forth story everywhere.
1) Story Plot??
2) Maria + Melissa = Marietta so who is Mellia? Mellia is one of Marietta's halves![deptheaven.wikia.com/wiki/Mellia]
3) Completed Yggdra on 1st round and got Good Ending but the King Wilmgard is not dead along with Algiery??
4) What does Maria do with Ancardia; revive King Wilmgard in (3)??
5) Correct me if I'm wrong as I read somewhere; did Maria kill King Wilmgard? (first scene as you can see her fleeing the castle) if so why does she assist him?
6) Whoever kill him; why didn't that person keep the body (as the whole world is searching for his body)
7) What has Yggdra have to do with this KitN or even to the Story?