What does ってのには mean?

Question

What does it mean in this context??

Answer 1

Let's start with the original sentence.

二度とあのピッコロ大魔王ってのには手をださねえことだな。

Now let's simplify it a bit to mean just: Let's not mess with Piccolo Daimao again.

二度とあのピッコロ大魔王に手をださねえことだな。

Now let's add back っての. っての is a variant of 〜というもの, i.e. "the one called..." or simply "that..." So we are adding the nuance of: Don't mess with the one called Piccolo Daimao again. Or just simply: Let's not mess with that Piccolo Daimao again.

二度とあのピッコロ大魔王ってのに手をださねえことだな。

Now let's add the nuance of "Well, don't know about other demons, but this one in particular we shouldn't mess with." Meaning roughly: That Piccolo Daimao? Yeah... let's not mess with them again. Or: Don't know about the other ones, but let's not mess with that Piccolo Daimao again.

二度とあのピッコロ大魔王ってのには手をださねえことだな。

For a discussion of っての, see the top answer at: What does ってのない mean?

For a really good illustration of the difference between に and には, see the top answer at: What is the difference between "に" and "には"?