The Night Wyvern was serious trouble. But Rhode did have the ability to resolve this issue. A young Night Wyvern was between level 75 to 80 and with Mini Bubble Gum's and Canary's strength and level 80 armor, they could resist it. However, they weren't guaranteed the victory since they were expert spell casters who were disadvantageous in close combat by nature. Moreover, the difference between their height and a five-floor-tall monster's was massive.
This would disrupt Rhode's battle deployment and this left him in a huge headache.