Macduff 

Spelt mac + duff.

Macduff is a loyal supporter of King Duncan and hence Macbeth's deadly enemy. He is Thane of Fife.

To remember these facts about Macduff, use the following mnemonic:

Imagine choosing between a mackintosh coat or a duffle (Macduff) coat.

But in the end, always loyal (loyal supporter of Duncan) to the same coat, even though it's marked and damaged. 

Besides, he always keeps his fife (small flute) (Thane of Fife) in his coat.