Series drift is usually blamed on the model. Look at the record instead. The character was described from memory at every job, and memory paraphrases as it goes. “Dark brown hair in a low bun with a violet pin” in frame one becomes “dark elegant hair” by frame four, and the audience watches a stranger take her place. The repair is clerical: record her once, as a registry entry you paste rather than retype.
Five fixed lines, always in order
Age — a number, and at this desk a mature one. Hair — colour, length and one habitual style. Build — two or three words, no more. Face — one or two details that survive any light. Signature — the one object or mark that identifies her at a glance.
Cite, do not paraphrase
Every prompt in a set opens with the entry, verbatim. Paraphrase is where drift breeds: each small synonym is a small new instruction, and the model obeys all of them faithfully. The entry exists so that obedience works for you instead of against you.