Who is Castle?

[Cavemanner]

I just played all the way through all the missions for the first time after starting and never finishing many times over the years, and being the kind of gamer I am now I tried to explore every nook and cranny in every level. There are spots on several levels that require some creative platforming where you can find a small, untextured cube that has the text "Castle was here" on it. Just wondering if anyone knows the story behind those.

[Max]

Look for the deleted scenes Fandom page. The whole story is there

[cambreaKer]

"castle" refers to one of the level designers, it's just an easter egg they put there