Much of his earlier life is unknown expect that he was born 200 hundred years ago. He survived the mermaid massacre lead by Charles Pownall in the late 19th century.
As a merman of Ryn's colony, he is very loyal to her and is willing to obey her commands. This is again displayed when he feels ashamed after disobeying her orders to stay in the cabin. He also displays a sign of respect towards Helen after he bows down to her when he learns of her mermaid heritage. That later levels up into a kind of love when he decides to show Helen his merman form, which impresses Helen.
In his human form, Sarge is tall and muscular with tan skin. He also has short black hair that is speckled with grey hairs on his head and on his goatee. He appears to be older than Levi due to the aging lines on his face. In his merman form, he has spikes protruding from and running down his back and a dark grey fishtail which lacks a barb, unlike the mermaids. He also has grey scales covering his entire body like the rest of the merpeople.
Throughout the Series
With the company Klesco Oil and Gas using sonar to find a place to drill and causing pain to all marine life through sound waves, Sarge arrives at Helen's house with Viv, Cami, Eliza, Katrina, and Levi. There, he acquires clothes and explores the objects around him. After some time, he and the others were moved to a log cabin where Ted Pownall and Elaine Pownall haven't visited in ten years. There they are able to thrive for some time hunting and fishing until they started showing signs of dehydration. Then, when Maddie shows Levi, Eliza, and Viv a candle flame, Sarge reluctantly joins Cami and Katrina on a fishing hunt.
After Cami gets attacked by a wolf, he carries her back to the cabin where she gets treated. He becomes ashamed of allowing harm to come to Cami as Ryn scolds him and Katrina for disobeying her orders to stay in the cabin Sarge and the others later returned to the water and succumbing to their natural instincts, attack some unsuspecting party-goers who play in the water. Shortly after that, they return on land and get new clothes. They soon stop at a gas station where they wreak some havoc and Katrina attacks the cashier.
For some time onwards, Sarge began to develop an attraction towards Helen Hawkins. This attraction soon became love at sight when Sarge decided to show Helen his merman form, which impressed her. After that, he seemed to try to meet Helen at any given opportunity and spend some time with her. When Helen, Sarge, and the other merfolk decided to take refuge in a cave, they found cave paintings that showed how humans and merfolk were together millennia ago. The relationship between the two was cemented when they held hands.
On the night of the gala, Ryn's colony successfully sabotages the Klesco drillship but the hook that was used to grip the drill string unwinds. Sarge goes in the way of Viv and Eliza, resulting in his neck getting slit. Ryn and the other Merfolk take his body and swim to his final resting place.
In "Borders", Sarge's ghost attempts to contact Helen to warn her about Tia and her colony in a dream. While this initially fails, Helen manages to find Sarge's ghost when she goes for a swim in the ocean at night. Sarge sends Helen a coded message which Hunter deciphers as a warning of an upcoming war.
In "Northern Exposure", Sarge's spirit reappears upon Helen's summon. She begs him for help to stop Donna's spirit from haunting her. He then leads Helen the US Naval Research Facility, where Donna's corpse is still inside. She then understands why Donna's not at peace. Helen thanks Sarge before he disappears.
- Sarge is the first bearded merman in the series.
- He is the second merman to debut in the show after Levi, as well as the second merfolk to die on screen.
- Even though he is named Sarge in the credits, Jerry puts his name up as "Frank".
- He is a natural protector and hunter.
- His true merman form is seen in "Primal Instincts" which Helen deems beautiful. Ever since then, he and Helen have developed an attraction.
- He is given a seashell necklace by Helen to remember her by which is later taken by Ryn, who returns it to Helen as a memento of her merman friend.
|— Sarge to Helen|