Flight of the Pendraig: Nidhogg's Escape

I'm working on a story on Deviantart called Flight of the Pendraig. It's about a 28-year-old man who died and was brought to Felarya as an Earth Pendraig (a draconic humanoid). He rescues an orphan Fire Pendraig from slavers and named her Ebony. After he and the remaining slaves journey to Safe Harbor with Jora, they discover that Safe Harbor is under attack by a Fire Succubus named Chastaine. After they defeated her and her girlfriend, he decides to take care of Ebony as his adopted daughter. Meanwhile in Hell, Chastaine is banished to Melchuum by her parents King Tranzix and Queen Faldhatée for violating the peace treaty between them and the Fire Pendraigs (Pendraigs are very protective parents. Think of them as the T-rex in The Lost World Jurassic Park only they can fly and breathe fire.) Anyways, Chastaine and her girlfriend are banished to Melchuum and encounter the former tyrant ruler of the Pendraig, Nidhogg. He was banished by his brother and the Guardians for siding with King Alcazath the Mad Titan and nearly causing the Pendraigs to become extinct. After freeing him with the help of a female Tedrek Titan named Galatea, the trio is trying to find a way to escape Melchuum and seek revenge on the Guardians. Meanwhile, some of the Pendraigs are still loyal to their tyrant king and are trying to free him. I'm trying to figure out how they'd be able to open the portal for him to escape. I'm open to any ideas and constructive criticism.