Patrick
The Eliminator took hold of Roxie and shook her around, tossing her away. The flames that the mouth spewed seemed to be effective... Until the Heartless behind the shield saw Nilus charge right through it and hit hard with the Hero's Origin Keyblade. That heavy blow knocked the shield out of the way for the main body of the Heartless to get slashed with No Mercy. 

The Heartless was about to counter attack with its shield but was hit several times in the back by Xanaro's barrage of attacks making it nearly fall over. The final blow was of Roxie's hammer conking it in the head and knocking it down for good. As it's body began to fade away to darkness, a swirling portal would appear, leading to  if they wanted to press on.
Kristen
Nilus raised his keyblade in the air with the sound of Victory! It was a glorious feeling and he was certainly riding that high. This was the excitement he had been looking for, none of that mundane citizen helping he was stuck with back in Olympus, he was searching for the adrenaline pumping, monster destruction, extreme fighting! 

"HAHA! Excellent work everyone! I've felt tougher bites from the hounds back home! 

The dark swirling portal intrigued Nilus, it was something he had never encountered before today. The darkness within it was a mesmerising sight, the swirling sensation almost felt alive. 

The monster had came through a similar portal.. Where had it come from exactly? Would there be more within the portal? Could Nilus take on that many? But what if the Portal was the key to stopping these monsters from entering Traverse Town.. Nilus turned to look at the three strangers who had helped defeat the Eliminator. 

"Roxie? Was it? You've got a real strong arm on you, the name is Nilus, you asked earlier but I was busy beating back that monster"

"Now listen the three of you... I have no doubt that the people of traverse town will sing our praise for aeons to come! That truly was a battle for generations to behold.."

"However... I don't believe it is over yet. This swirling darkness must be the key to stopping any monsters from entering Traverse Town again. I suggest we enter it and defeat whatever mad and evil amalgamation lies beyond it! Our Heroism shall win the favour of the Gods tonight, let no fear take over!" 

And with Nilus' monologue of a speech that was never as cool or impactful as he thought it was, he held his keyblade high in the air, and charged through the portal... Very recklessly
Francine
Alex looked at the others and shrugged. "Well after hearing that we got to go right? I don't know how much help I'll be, but I'll do my best." She walked over to one of the trees, and held out her hand. A second later a squirrel crawled down from the tree, and into her hand. "Could you let momma know I won't be home for dinner?" The squirrel cooed in agreement. "Thank you friend." Alex would scratch under the squirrel chin. Before it scurried up the tree again. Alex turned and walked towards the portal. She stopped just before she crossed it. Alex took a deep breath, and stepped through the portal.
Francis
Xanaro stands still, glaring at the portal for a few moments. It's not exactly his assignment to go world hopping, but, it could lead to more hearts to free. He also pretty much ignored nilus's speech.

So, he walks through the portal calmly, paying close attention to his surroundings as he does.