In Colin books where does Lewis come from?

You're likely referring to the "Chronicles of Narnia" series by C.S. Lewis.

However, there's no character named "Lewis" in the books. Are you thinking of another character, perhaps "Tumnus"? Tumnus is the faun who befriends Lucy in "The Lion, the Witch and the Wardrobe".

If you can provide more details about the character you're interested in, I can help you find the answer.