Runa opens it, and on the other side is...a small crystal. Actually, it was there from the beginning, just everyone was so focused on the new arrival they didn't notice it. So really, the door is pointless.
Slash puts his book away and looks around.
"Wait!" Feturu calls out. "Don't open the-"
But it was to late, as Hepohepo appeared again.
"Hi again." He says. "So you want to get out? Well, prove yourself."
He summons a hydra, surrounded by chaos energy, and leaves. "Good luck." He says mischievously.
Tangi, Runa, and Feturu get into defensive stances, Feturu summoning her rapier, Runa his scythe, and Tangi charging a blast from her cannons.
Slash draws his sword, which had a mysterious amount of Venus Adept energy around it.