Tom Bombadil

Always the mystery of Middle-Earth is the character of Tom Bombadil.  His character is never fully explained, nor are his origins clear.   He serves as a sort of pseudo God-like figure, seemingly impervious to the evils and charms of the Ring, yet helping the Hobbits on their journey to Bree.  He is, at the same time, unwilling to give direct help (by keeping the Ring safe), instead encouraging the Hobbits to continue fastly.

Twice Tom comes to their aid; once in the Old Forest, he releases the Hobbits from the sleepy evil song of the Old Man Willow.  Again, after they have set out again, he returns to free them from the spell of the barrow-wight, a fearsome and malevolent spirit.