Does this AU have any characters other than Sans/Teller that are notable? A human, maybe? Perhaps a Toriel, or an Undyne?
Oh yes! There are! In fact the original person who led the crystal golem project was Crystaltale Undyne. She was tasked with creating the ultimate warrior and protector for the hero when they were to arrive to save their world.
She was given this task because she was very skilled in not only crystal craft but with a spear as well. So she was able to impart spear techniques into her creations.
Unfortunately she was forced to include Sans's magic after he had died and that set the progress back by a lot. Cause not only was she trying to make the ultimate shield and the ultimate spear into one construct but now she had to redo the whole body design to fit in Sans’s magic.
It was quite the stressful time for Undyne but she never gave up. Even when it was clear they were running out of time.
She and the others who were helping her managed to incorporate Sans’s magic and the defense mode relatively well but with the time crunch a lot of the project was rushed and as a result Teller lacked the ability to see and can't easily access his attack mode.
Teller technically still has this attack form and can shift into it. Unfortunately it's too unstable to be used, unless it was an emergency, since they never got fully completed.
Their are other characters in this AU as well, in fact Asgore was also a big contribution to Teller's construction.
