Honestly, Alex didn't want to continue fighting the spider lord. The other party was just too dangerous for his taste.
He admits that he was originally excited to fight a Calamity rank beast, but he wasn't reckless enough to want to fight a creature he couldn't even see clearly.
Right now, Alex was only able to keep the spider lord at a distance by sending his sword fragments after the other party's afterimages and where he thought he would head to next; this was why the spider lord hadn't been able to approach Alex, but how long would this continue to play before the other party finally figured him out?
Also, he could sense that the battle between the mages and the army of spiders was almost coming to an end. Lucas and the other Saints would definitely rush over to try and help him.
With how fast the spider lord was, not only would they be in danger if they came here, but Alex's secret would also be revealed if they saw him using the space element.
