Shim was a giant who was, for a time, as small as a dwarf.
Shim met Merlin, then Emrys, and Rhia while they were eating honey that he was swimming in. At the time he was smaller than the smallest dwarf, barely up to a man's knee. He accompanied them on the quest to defeat Stangmar in the Shrouded Castle. After infiltrating the castle, Shim became lost in the commotion of the fighting. Later he emerged just in time to cast himself, willing, into the Cauldron of Death, destroying it.Instead of dying, Shim began to grow to the full size of a giant. The ghouliant forces of the castle then tried to slay Shim, but he stamped on them starting the prophesied Dance of the Giants which destroyed the Shrouded Castle.
Shim was very helpful to Merlin in his other quests on Fincayra.
A few hundred years later in Avalon he started getting smaller and is now the same size as a dwarf.
His favorite phrase is, "Certainly, definitely, absolutely."