So, Finally reached The Realm of Damnation and everthing is all smooth until I come up against This Boss called Skorn! This monster has 5 bars of life! so I get him down to his last lfe bar and thats when he Biawch Slaps me to hell… 
So I go for back up and invite a friend or two to help kill him (Skarn) and to my dimise…nobody can portal in. So is this a Solo task and I have to wait until I’m stronger in order to beat Skarn? Or is there a way I can do this in a group?
Yes, the Skarn fight is a solo story dungeon instance, i.e. you have to solo it.