Origin
Kilroy was a Swedish hero that started out as an Italian imitation of The Phantom called Amok, who was a white man who was raised in the Jungles of Burma and when his fiancée was kidnapped by a criminal group known at Scorpio he puts on a mask, some armor and the symbol of Mascherona the dragon on his chest and goes after them.
He is soon known as The Shadow Who Walks, and even after rescuing his sweetie keeps up the guise of Amok / Kilroy.
While starting out as Amok in Italy, the character proved more popular in Sweden as Kilroy so that when they ran out of Amok stories to adapt they started creating their own Kilroy adventures, while forgotten in his country of origin as Amok, he still has enough of an audience in Sweden that he returned in the 70s.