Martatus is a whimsical being that not a lot is known about by normal people.
He is a friend of Sir Leonard's, and is extremely intelligent.
He lives in a castle from the days of old, that once belonged to a king. Tales have it that he once was a pet of the king who owned the castle, and was treated as a pet, rather then a sentient being. Martatus may seem innocent, but Sir Leonard knows in fact he is extremely powerful, for in a spout of rage, he banished the one who called him his master, along with all the servants and people living in the castle to an unknown realm.
He dislikes leaving his castle and fears that he may lose control of his temper again, so he hardly ever goes on quests unless it's of a serious matter.
Well versed in magic, he is the perfect person to go to for any research and advice that is needed, for he has the largest library in the world in his castle.

side note: his hat acts as a portal back to his castle. If it fits it goes there. He can slide himself into it and at the end of it turn it inside out so it goes to the castle with him.