Adrian Edmondson's chilling and slyly humorous, camp (no, not the concentration camp but a camp manner) commandant is called Grandma because he sits in a corner knitting in the evenings. His real name is unknown. Edmondson's performance, full of easy patter, is sinister and makes you shudder as you laugh, a not entirely comfortable feeling.
Tom Stoppard's plays are brilliant, peopled full of characters that stay with you. Leopoldstadt may be his last play as he has suggested, but I think it is his most personal.