Which character was a executive producer of M1 , M2 , and M3
SELECT DISTINCT ?x0 WHERE {
?x0 a ns:fictional_universe.fictional_character .
?x0 ns:film.producer.films_executive_produced M1 .
?x0 ns:film.producer.films_executive_produced M2 .
?x0 ns:film.producer.films_executive_produced M3
}