Merlin

Merlin is the deuteragonist of the Magic Tree House series. He is a powerful wizard that tasks himself in mentoring Jack and Annie Smith. Though wise in his own right, Merlin's absentmindedness tends to complicate his teachings—especially in the eyes of his crotchety familiar, Archimedes.

Physical appearance
Merlin is an old wizard with a white long beard and a big nose. He also wears a blue long cap and robe (patterned with moons and stars), including a pair of black shoes with golden buckles, and spectacles on his big nose.

Personality
Merlin is a wizard of unspecified origin who can only be seen in his headquarters, his Magic Tree House. He is a very wise character who believes in the philosophy of "Brain over Brawn." To this end, Merlin values education as opposed to the war-training philosophies shared by much of the rest of society. Despite his wisdom, he can be absentminded and forgetful, as well as clumsy.