I placed the mask and the five elements. I got a dialog of how the mask changed but where is Haleabus and the portal that's supposed to open? I picked up the mask and searched the castle but couldn't find anything? The only place I can't get is into the doors by the pool and I never found any key or anything to open those doors and the changed mask didn't work. I'm stuck. Where is the portal?

Haleabus is behind the locked door directly opposite the entrance. The key is (I think) hanging on the wall in the kitchen, (someone correct me on this if I'm wrong) I know I found it fairly early on. The mask IS the gateway, you need to give it to Haleabus to make him vulnerable. Without it you can't hurt him at all, and he can sure hurt you.