[commoner]

You're probably right. Kastelo previously launched a service called Arigi that was later discontinued. The announcement notes that "arigi" means "to amass · to gather · to put together" in Esperanto.

https://webcache.googleusercontent.com/search?q=cache:IAwDkf...

[0xADADA]

or its a tech startup that just named it 'Castle' spelled with a K-elo to make it unique