Roan was still the main commander of the army, so Frin had no choice but to do what he told. In any case, Roan wouldn't risk his safety, making sure his commands were sent while keeping a safe distance. That being said, he headed straight into the Soul Gem Dimensional Realm. As for the demon beasts that stayed behind to protect him, they were simply told that he was using a special concealing technique to hide from them.
If the Dimensional Realm didn't undergo that change, Roan wouldn't have done it like that. He would first use his White Star to gather Light Element and keep the Spiritual Sense bending skill working. If he felt the presence of the Transition Realm Zasfin, he would enter the Soul Gem Dimensional Realm straight away. However, he knew for a fact that he would be barred from entering this time. He didn't want to risk it, so he went straight inside it after Frin left. All the orders he had to give were given, so he wasn't that much concerned either.
