A Note on Mar's Bizarre Language:
Basically when the Highest speak to one another, they often use a form of communication that uses pictures as well as words--- A language that allows them to convey precisely what they mean (Along with amorphous concepts like Highest names, which essentially invoke the Highest when someone says one). It actually is very similar to Andalite thought-speech in character, with one exception:
It is next to impossible to lie to someone in it, because the language also shows whatever the speaker is feeling in regards to the statement. You can, however, manipulate people with true statements if you're smart. And this is part of why despite being called the Lord of Lies, you're rarely going to find a story where the Devil lies about anything at all. Deceives, yes--- Lies, no. XD
Mar tends to speak in a dialect that makes this easier to do-- Which, other than his short German vacations, is why he appears to have a distinctive weird accent in any other language he speaks.