Dr.Chakma said, “Both these stories say Alavaka Yakkha was ferocious and Buddha subdued him.”
That is true. As I explained they have “rough character qualities”. Again, Alavaka yaksa is a better word than Alavaka yakkha.
However, they don’t normally kill. Alavaka Sutta does not say he tried to kill a prince, and I did not see such an account in the link that you gave; however, I may have missed it because I do not have time to read the whole thing.
In general, it would save me a lot of time, if people can make it clear where a given quote is within a quoted source, or just copy the relevant text from the source and paste it in the comment, together with source.