Just to the right of the Village in the opening location. The three areas of the island are the Village, the Castle, and the Mill.
Go right and you will see the castle
There is a castle on Astro Knights Island, in the kingdom of Arturus.
On the top of the castle
You get it in astro knights island. you go to the guy to the right of the castle and he will give you some.
If you land back on Poptropica, your spaceship is parked atop the castle. This is also its location when you have beaten the island.
Nothing
One common glitch in Poptropica's Astro Knights Island involves getting stuck at Mordred's castle door. To bypass this issue, try resetting the quest by leaving the castle and re-entering, or restarting the island entirely. If the glitch persists, consider contacting Poptropica's support team for further assistance.
on astro knights island
The arrow is at the castle
if you mean in astro knights, the mcm is in the library in the castle
astro knights island
astro knights
The kingdom of Arturus is on the planet Poptropica. It consists of the Village (Main Street), the royal Castle, and the Mill.