Elden Ring PC | Elemer of the Briar boss fight co-op w/1 summoned player on NG w/achievement

(I realized I forgot to start recording, so I started it as soon as I entered.)

Elemer of the Briar is the boss of The Shaded Castle, located in Altus Plateau.

Drops:
21,600 runes (+20% runes bonus since I was wearing Golden Scarab talisman)
Marais Execution's Sword
Briar Greatshield
Elemer of the Briar achievement (Steam / PC)

Elemer of the Briar
"Elemer of the Briar is a Great Enemy Boss in Elden Ring. Elemer of the Briar is an extremely aggressive human boss and is found in The Shaded Castle in Altus Plateau. This is an optional boss as players don't need to defeat it to advance the plot of the game."
https://eldenring.wiki.fextralife.com/Elemer+of+the+Briar

Marais Executioner's Sword
"Marais Executioner's Sword is a Greatsword in Elden Ring. The Marais Executioner's Sword scales primarily with Strength and Arcane and is a good Weapon for melee users who want to output high damage. Infuse the sword with energy, then fling it forwards in a corkscrew attack. The sword continuously deals damage while violently spinning. Charge the attack to increase reach and duration of the spin."
https://eldenring.wiki.fextralife.com/Marais+Executioner's+Sword

Briar Greatshield
"Briar Greatshield is a Greatshield in Elden Ring. The Briar Greatshield is a Shield that scales primarily with with Strength. Greatshields weigh a lot but provide the best protection in the game. Greatshields provide a greater value of blocking and protecting oneself from enemy and boss attacks, but greatly increases the weight and reduces the player's mobility. This type of shield works best at reducing damage or guarding instead of parrying."
https://eldenring.wiki.fextralife.com/Briar+Greatshield

The Shaded Castle
"The Shaded Castle is a Location in Elden Ring. The Shaded Castle is found in Altus Plateau. A castle found in the northern region of the Altus Plateau. Head north through the valley between the Mt. Gelmir and Altus Plateau regions, heading north from the Altus Tunnel to find your way to the Castle."
https://eldenring.wiki.fextralife.com/The+Shaded+Castle

Elemer of the Briar achievement
https://www.trueachievements.com/a354517/elemer-of-the-briar-achievement