Marvin was hoping to chance upon the Black Dragon on the 2nd floor.
He wasn't sure if he could emerge victorious against the other Ancient Chromatic Dragons.
Although their strength would be substantially reduced under the restriction of the Shapeshifting, they were still equivalent to Legend Wizards with powerful bodies.
Only Black Dragons had no magic abilities, so Marvin could deal with them.
This was said to be the reason behind the Black Dragons' betrayal.
Although Marvin was interested in the ancient history, this wasn't the most important thing right now.
His current priority was to get to the library.
As for the Nightmare Boundary, although he volunteered, he wasn't part of the main force.
With people on the level of Blade Master Kangen and Professor taking charge of this matter, Marvin went with the attitude of being an extra and wanted to see if he could get any benefits.