Demetrius is married to ロビン and lives with his daughter マル and step-son セバスチャン. Maru is his daughter with Robin, and Sebastian is Robin's son from an earlier relationship. It is assumed that Demetrius is Robin's second husband, because there are 2 books in the bookcase of their room titled "Maximizing Your Second Marriage" and "Practical Tips For First-Time Step-Dads." Demetrius is very protective of Maru, as shown in her two heart event.
When your total earnings reach data-sort-value="25000">25,000g Demetrius will come by your farm in the morning and tell you about some research he needs help with. He will then volunteer to improve The Cave to either attract Fruit Bats or to produce Mushrooms.
I was conducting a field study the other day, and I found this specimen.
I hope you find it as interesting as I did.
-Demetrius
クエスト
"Crop Research": Demetrius will send you a letter on the 20th of Summer requesting that you bring him a Melon. The reward is data-sort-value="550">550g and 1 Friendship heart.
"Aquatic Research": Demetrius will send you a letter on the 6th of Summer in year 2 requesting that you bring him a Pufferfish. The reward is data-sort-value="750">750g and 1 Friendship heart.
Demetrius may request that you slay a certain number of Monsters or bring him a random item at the "Help Wanted" board outside Pierre's General Store. The reward for slaying monsters varies by the number/type of monster, but is always an amount of gold. The reward for an item delivery quest is 3x the item's base value and 150 Friendship points.
ポートレート
Notes
If Robin is constructing something on your farm on the nights she and Demetrius go to the saloon, he'll go and dance by himself.