The guidewords for the word Serpent may be Serbia and service. The serpent, in layman's terms, is a snake. It is one of the oldest and most widespread mythological symbols. The word is derived from Latin serpen, a crawling animal. Snakes have been associated with some of the oldest rituals which are well known to known to humankind. The snake represents the dual expression of good and evil. It is termed as evil in Genesis, where it lied to Eve and she ate the forbidden fruit.
Snake is good because in some countries it serves as medicine. To conclude I can say, “Each and everybody has a bad side and a good side”