Astall is the owner of Blue Castle, a castle that is in risk to be destroyed, because someone stole the 20 blue stars.
Astall, knowing that his castle could fall, he ask for help of the bravest ones...Mario and Crash. He never appeared in a blooper, (only cameos) and only appeared in a single series.
He appear as cameos in bloopers, but it don't make sense, since he dies at the last episode.
First and last appearence
He appeared in every episode of the series, but at the final episode, while trying to get the major blue star, he notices that Mario and Crash are going to die, and if he gets the major blue star, he would leave without them.
He uses his powers and teleport them to the blue castle, Crash and Mario leave the blue castle, and outside find that he died. Since he's dead, he didn't get the major blue star, and since he needs 20 stars, and he only have 19, the blue castle gets destroyed, and Crash and Mario return to the mushroom kingdoom. He could be alive, and have the castle safe.