Mermutany

His friends are Koonboat Navasharck (Navasharck could be considered his best friend), Meema Bubbles, and Jack CopperZ.

Mermutany seems to be aware of all the approaching bosses through the message sent before nightfall or any summoning method, and showed this to the team through his drawings, in addition to the Twins.
Despite belonging to the same universe, Mermutany travels between Stickmen Vs The Twins and Stickmen vs Golem, since he obtains equipment after Plantera despite not being present in Stickmen Vs Plantera.
At the beginning of the series, the bullets Mermutany uses leave yellow trails, even though close-ups show they are musket balls. In Terraria, musket balls usually leave a red trail.
At the end of Stickmen Vs Queen Bee, his lyrics are shown (most likely from Terraria).
In Stickmen Vs Queen Bee, he commented, "RIP my Minishark, but I have Navashark, yessss! XD." This was a hint about Navashark's arrival in the next episode.
At the end of Stickmen vs. The Twins, it is shown that he left the game and the team, with no sign of returning. However, he reappeared in Stickmen vs. Golem after an eight-year absence.
Mermutany doesn't like unpeeled pineapples because their shape resembles her ex's hairstyle

Within the group, Mermutany focuses on the Ranger class from Terraria, using firearms and bows, though he also uses many other tools throughout

Stick men versus queen bee
Minishark with "generic ammunition" (the bullets shown do not resemble any ammunition in Terraria and may pierce or ricochet off blocks inconsistently).
(lost after being attacked by the queen bee)
Red wrench and cables, rock trap with orange pressure plate
Magic mirror
Stick men against the wall of meat
Obsidian Skin Potion (x1)
Grab hook
Fury fused with flaming arrows and arrows of hellfire.
(lost after being attacked by the Wall of Flesh)
Melted peak
Demonic torches
Meat wall treasure bag
Pwnhammer (obtained from the boss)
Ranger Emblem (obtained from the boss)
Demon Heart (obtained from the boss)
Stick figures against the Destroyer
Mini shark with musket balls
Ranger emblem (presumably)
Stick figures vs. Skeletron Prime
Pwnhammer
Umbrella
Megashark with musket balls
Meat gauntlet (Jack's past, then passes to Meena)
Ranger emblem (presumably)
Skeletron Prime's Treasure Bag
Skeletron Prime Trophy
Stick figures versus twins
Megashark with Crystal Bullets (previously uses Musket Bullets against Pirates)
Ranger emblem (presumably)
Stick Men vs. Golem
Sniper rifle with nanobullets
Piranhagun
Venus Magnum with chlorophyte bullets (then recharges with nanobullets against Golem).
Grab hook
Shellphone
Megashark (gives it to Jack)

Several boss battles later, Mermutany appeared unexpectedly, taking down a Lhizarhd that was about to stab Jack with the Seedler and finishing off other Lhizarhd with her new Piranhagun and Venus Magnum. She then joined the party and counterattacked a detached Golem, landing a sustained attack and disabling its head. Jack stared at her in amazement, unable to believe who was standing before him, before she teleported back home using her Shellphone.

When Mermutany left the house, Jack invited her back in, but she calmly handed over the old Megashark before settling into a nearby wooden house.

Along with the others, Mermutany left the house and began fighting off hordes of pirates. Finally, Meena grabbed the coin gun and shot down the Flying Dutchman, ending the pirate invasion and surprising everyone. Later, a message appeared that read, "This is going to be a terrible night." Mermutany didn't react at all, possibly because she was a novice Terraria player on Hard mode and was unaware of the Twins' spawn message.

That night, while the gang relaxed under a tree and stargazed, the Twins appeared. Mermutany and the others entered the house, only to have the roof ripped out. She then called Meena for long-range support. When KOONBOAT was trapped running on Retinazer, and Meena was slowly aiming, she freed him with a single shot. By the time the Twins entered their second form, she increased her movement using the grappling hook, but Retinazer countered. Meena reminded NavasharK and herself that dawn was approaching, so the trio attacked with all their might. Because of this, Spazmatism was drawn toward them, simultaneously smashing all of KOONBOAT's orange juice bottles, which enraged him. When time ran out and Spazmatism tried to escape, they stopped him, and the two heroines finally finished him off. Finally, Mermutany reviewed NavasharK's situation and, unable to tolerate Meena's overacting, left the game.

Mermutany is seen opening the front door, which hits JackCopperZ and crushes him, but he doesn't notice, as he opens his umbrella with a Pwnhammer and heads towards the Corruption. While destroying the demonic altars, he receives a message: "You feel the air getting cold around you..." He returns home and looks out the window, showing his drawing of a four-armed boss with a skull. He then suggests everyone go outside to defeat Skeletron Prime.

Just as the battle was about to begin, Skeleton Prime flew toward the new house built by an unknown player named Meena. Upon entering the house, they saw that Meena was under attack. She jumped onto a platform and began firing her newly created Megashark. In turn, it caught the Flesh Gauntlet and lured Skeleton Prime. While KOONBOAT held the gauntlet, it destroyed Prime Cannon. After the boss was finally defeated, it took the treasure bag and gave the unconscious NavaShark an SP trophy. Upon waking and seeing the trophy, NavaShark flew into a rage, eventually creating a hole near Mermutany's feet. But then, a message appeared: "Pirates are approaching from the west!"

First day of Hardmode. Mermutany lay in bed, watching the hours drift by. That night, as JackCopperZ finished trapping a butterfly in a bottle, she awoke. The message appeared: "You feel vibrations from the depths..." Frightened, she grabbed a piece of paper and showed her friends a drawing of a worm-like monster, which reminded them of the Eater of Worlds. Outside, she prepared with her Minishark. When the Destroyer was summoned, it attacked first, catching her attention, and it lunged at her, but she dodged the attack, falling to the ground. JackCopperZ shielded her from its laser beams. After that, she continued attacking the boss and killing Probes. When she and her friends delivered the final blow, Mr. Fallen Star interrupted and grabbed the loot.

This time, he joined JackCopperZ's world along with KOONBOAT and NavaSharK. In the underworld, JackCopperZ killed a voodoo demon, causing it to nearly drop the voodoo guide doll it was holding into a lake of lava. Just before it hit the lava, an obsidian-skinned mermaid used her grappling hook to emerge from the lava and retrieve the doll. She scolded Jack for his carelessness, much to his confusion. To make him understand, she drew a picture indicating what would happen if the doll fell into the lava: it would decide the fate of the player and the world itself.
Ready, she waited for JackCopperZ to throw the voodoo doll into the lava, but he failed. Instead, Mr. Fallen Star somehow reached the underworld and fell into the lava, shooting a jet of hot lava that burned the doll. 'Wall of Flesh has awakened,' she declared, and began her movement. Mermutany moved continuously with her grappling hook and fired hellfire arrows at the boss and its offspring (The Hungry One and The Leech). After saving KOONBOAT from a Hungry One and damaging Wall of Flesh to low health, it moved much faster, collided with her, and grabbed her with its tongue, draining her health. With JackCopperZ and KOONBOAT defenseless, she fired a hellfire arrow into the lava as a signal to summon NavasharK. Finally, Wall of Flesh was killed by a bite from NavasharK.
Mermutany broke the demon cube and looted the boss's spoils, then climbed aboard NavasharK with his friends as NavasharK flew to the surface. After opening the treasure bag, he gave JackCopperZ a Pwnhammer, KOONBOAT a Demon Heart and a Breaker Sword, then climbed back onto NavasharK and flew away.

While Jack CopperZ was collecting honey, Mermutany joined his world, along with KOONBOAT. Despite being curiously examined, Mermutany had a cold attitude toward Jack CopperZ, causing him to panic and flee. Upon seeing him collecting honey, he was surprised to see a small bee—the result of the hive being destroyed—attacking him. Annoyed, Jack took his Minishark (giving him his Night's Edge) and shot at the bee, missing. The bullet ricocheted and broke a bee larva, summoning the Queen Bee. Mermutany retrieved her weapon and fired seven bullets that perfectly pierced the seven bees the Queen Bee had released. The Queen Bee dodged the bullets and lunged at Jack CopperZ and Mermutany. Jack missed throwing his sword at the Queen Bee, causing her to strike Mermutany, sending her crashing into a wall and sinking into a pool of honey. After the Queen Bee is defeated, Mermutany swims to shore and is rescued by Jack CopperZ. Suddenly, she notices a wrench in her hand and realizes she was the one who set the rock trap. Embarrassed, she throws the wrench away. Unfortunately, the rock she releases (triggered by Jack CopperZ) breaks another larva and summons a second Queen Bee. Being very weak and unarmed, her last resort is to teleport Jack CopperZ back home and leave the game before the boss can attack them. Back on the surface, Jack CopperZ finds a note she had left, which simply reads, "See you again... somewhere."

Mermutany, who rarely smiles or expresses emotion, is usually very serious and, most of the time, manages to maintain a calm and indifferent demeanor. However, beneath her cold exterior lies a kind heart towards her teammates, especially her best friend, NavasharK.
He knows all the bosses in Terraria (up to Skeletron Prime) and often uses his drawing ability to illustrate their appearance, summoning methods, and mechanics.

As a ranged Terrarian, she is very fast and agile, as well as strategic, since she can devise a plan to deal with certain bosses and use stealth to avoid taking damage. She also possesses good reflexes and great accuracy, allowing her to move quickly between platforms to fight bosses more effectively and accurately shoot a rotating Retinazer, which Meena has difficulty aiming at.

Mermutany has white skin, dark green hair, and fuchsia pink eyes. Being part mermaid, she has visible fins on the sides of her head and wears several seashells in her hair. She sports a shoulder patch with a nuclear symbol and is a stick figure, like everyone else on her team.