Noi

Noi is introduced in the second series. He was first shown in dragon form being pursued by Michael's Red Dragon form. He first met Shu and Bouquet and used his powers to reawaken their shadows when they are attacked by Rosekstan soldiers and Michael's Red Dragon form. He does have a rivalry with Marumaro when he meets him and reawakens his shadow. He is later revealed to be an 'Investiture Being,' but Shu, Bouquet, and Marumaro are okay with that. When it comes to the final fight with Rudolph, Noi unleashes his full power and matures his dragon form. He manages to fight Rudolph until the Shu/Blue Dragon recovers. After Rudolph is destroyed, Noi leaves with Lota and Hildegard. Noi has a baby black dragon form.

Noi rarely turns into his dragon form to fight, but he often merges with Blue Dragon to form a powerful version of him with a forcefield ability. His dragon form later matures during the fight with Rudolph in his flying castle. (source: wikipedia)