Elden Ring PC | Tibia Mariner boss fight solo on NG

Tibia Mariner is located in Summonwater Village. Not a necessary boss, but easy and drops two items that can be beneficial, including an item that can be traded for incantations, weapons, and a unique smithing stone, as well as a unique Spirit Ashes you can't get anywhere else.

Drops:
2,400 runes
1x Deathroot
1x Skeletal Militiaman Ashes

Tibia Mariner
"Tibia Mariner is a Field Boss in Elden Ring. These hunched skeleton dress in lace and ride a ghostly boat. It steers its vessel and attacks the player with a large horn and the aid of undead Skeletons. They are optional bosses, as players don't need to defeat them in order to advance in Elden Ring."
https://eldenring.wiki.fextralife.com/Tibia+Mariner

Deathroot
"Deathroot is a Key Item in Elden Ring. Gurranq Beast Clergyman seeks and devours these. Key Items in Elden Ring include a wide variety of items found in specific locations or given by a related NPC, which are used to unlock areas, quests, and to further progress the game's story."
https://eldenring.wiki.fextralife.com/Deathroot

Skeletal Militiaman Ashes
"Skeletal Militiaman Ashes is a Spirit and Summon in Elden Ring. Skeletal Militiaman Ashes summons the spirits of 2 skeletal militiamen who live in death."
https://eldenring.wiki.fextralife.com/Skeletal+Militiaman+Ashes