In Howl's Moving Castle
, Mari Parry is Howl
's young niece. The two are very close, and are pictured speaking welsh to eachother very rapidly. She seems to be about 5 and is known to deliberately unplug her brother's computer while he's using it, indicating as willful a personality as the rest of the family perhaps. Howl tends to spoil with gifts her when he visits.
Mari has an older brother, Neil; her parents are Gareth Parry and Howl's sister Megan.