Dwarf refers to a person with one of several varieties of a specific genetic condition called dwarfism. A dwarf has disproportion of body parts. This is generally caused by a genetic or nutritional disability. Any adult human below the height of 4'10 (147 cm) is considered a dwarf.
One Piece has a great story and does not have a lot of filler episodes.
Permanent, or non-resorbable, types of filler are not used as much as temporary ones due to the fact that they can last for more than ten years. However, if you would rather have longer-lasting effects then they are the way to go.