Two worlds, one cast library
Isekai lives on contrast. Draw your lead in ordinary clothes (a bomber jacket, an academy blazer) and keep the convenience store and the train crossing in the set library for flashbacks. Then draw the other world: a castle courtyard at night, a frozen lake clearing, shrine steps in the rain, a frost mage's regalia, a wandering swordsman's cloak. Because outfits are separate sheets, the same lead can cross over mid-episode: one take in the jacket, the next in the cloak, same face throughout.
The preset cast includes a mentor with an eyepatch, a villain in a high-collared coat, an ice mage and a wandering musician, which is most of an isekai ensemble before you have drawn anyone.
Episodes that build a world
The draft reads your show's premise and the synopses of earlier episodes, then writes two to four beats for the next one. For an isekai show that means it remembers which rule of the world was revealed last time and what the lead still does not understand. Write the premise with the hook you care about ("she can read the charms but not the people", "the arm came with him and it works differently here") and the drafts keep pulling on that thread.
Each beat is one continuous shot of six to fifteen seconds, so big reveals are staged as moments: the courtyard torches guttering as the villain turns his ring, the ice cracking under a first spell. Action beats get speed lines and impact frames; quiet beats get the slow push-in.
A season in thirty episodes
A show holds thirty episodes, which is a full arc for a mini isekai: arrival, first ally, first rule, first loss, the rival, the villain's offer, the choice. Finished episodes line up on the show's public page in order with their posters, so a viewer can start at episode one. When the arc ends, start a new show for the next world and attach the same cast.
Original worlds only
Everything here is original by design. The cast is yours or the site's own presets, the sets are drawn from your descriptions, and the drafts are asked to invent rather than borrow. That is a feature: a world nobody has seen before is the point of the genre.