I am looking for the black dog that killed marta and took the secpter..

Ok dude here's what you need to do. First, you go to pirate's cove which is located along a river you can use the ship to go through.Second you need to go through the dungeon and fight captin crow [make sure angelo knows sarcastic snigger which you get from leveling up charisma cause he will raise his tension to the maximum and sarcastic snigger lowers enemy tension and it well help you get a few extra moves with the others ] once you defeat him you'll get the illuminated sea chart which will help you get to the island which you couldn't get to before . Then you find the town there and save there. After that you go find a rock formation where it looks like a giant
Monkey bar then follow the giant shadow of a bird in flight to a big black thing then you go find the town agian and go and talk to the tribal chief after that you go find the rock formation and then you fight thegod bird after she is defeted she will fly you to her roast where you will need to fight a giant griffon called giemon then after that you get the abillity to fly after that you go to a place no acssesable from your ship and you find the town there then roam around untill you find a little girl in a room with a giant light blue cyclopes then after thatyou go and find a place with a orc guarding the entrance to a room with bars as a wall on one side then you get the leaf and get out of there and use the flying ability and follow the leaf and then you should find the dog that killed marta

Looking back to paste boss battles I assume that the hell hound and sir Leopold will be quite a challenge. One good way to beat the hell hound boss is to use your monster team, but only if you have very powerful monsters example: Talos the living statue and Goldman. Those two have a lot of HP and they're attack stats are pretty high. Or you can do without and fight the normal way. The choice is yours but try doing a little bit of both. That's what I did with doughlmagas and it worked like a charm.

And to answer your question about where the black dog is heading, it has ended the blood line of all sages but one. And that would be sevella. The dog is going to the church at the top of sevella on that huge rock chained in the sky. But you need to fly there that's the only way to get up there. The black dog boss will be really hard so level up until you are in the 40s or 50s. Sir Leopold is going to kill the abot of sevella. Then I believe raphthorn will be free.

The dog is heading for the church at the top of sevella.