The Petra figure is now available for pre-order for 15,000 yen (about $143) and ships out in August.
Now that the set is complete, more characters are joining in: most recently the new maids Frederica and Petra, as seen in season 2 of the isekai series.
You can also pre-order the Frederica figure for 17,000 yen (about $162), with orders set to ship out in November.