The demon returns in "Play Date" where Ice King and Abracadaniel bring him back by reading an inscription on the Blood Sword. He grabs them both and threatens to kill them unless Finn returns his blood. Finn breaks the Blood Sword in half and sends Kee-Oth's blood back to him, causing him to grow greatly in size and power. He then grabs Jake, thinking he is Joshua (and unaware that Joshua is dead), and teleports away.
In "The Pit," Kee-Oth holds Jake hostage and soon learns he is Joshua's son though becomes frustrated at the latter's laidback nature. Finn and Lady Rainicorn pursue Kee-Oth back to his fractured dimension after learning the way from Joshua's old video tapes (which had partially been taped over by Jake with romantic scenes for Lady). After seeing in an old video how Joshua had kept Kee-Oth from sucking his blood by drinking holy water, Finn defeats Kee-Oth by tricking him into sucking a fake Demon Blood Sword that was actually grape juice blessed by a "priest" (really Shelby in a movie outfit). Kee-Oth then explodes, and Finn and Lady took Jake home, along with Kee-Oth's previous captive, Samantha.
Kee-Oth's initial appearance was that of a large, black-skinned demon with large, bright green eyes. He has thin legs, and torn up black wings. He also possesses a long, slightly curved tail and two horns, one of which has had the tip broken off. His large, gaping mouth is filled with sharp teeth and his ears are long and pointed. His muscular arms are long and gangling, and end in flat hands with long, pointy fingers.
When his blood is returned to him via Finn breaking the sword, he becomes almost four times larger and his skin becomes a bright red. Whenever he is summoned, banished, or teleporting he is engulfed in flames and before disappearing when the flames die down.
- "Is That You?" (replay from "The Pit")
Appearances in other media
- He appears as a non-playable character in Adventure Time Battle Party. He is a neutral monster who lives in the bottom lane. He will grant a temporary increase in attack power to the team who defeats him.
- The production art for the Blood Demon shows him with green eyes, but in the actual episode he has red eyes. However, they were changed back to green in "Play Date."
- To summon Kee-Oth, one must say: "BUTYRUM LAC SUREPO KEE OTH PRANDIUM."
- He thinks that Jake is Joshua, constantly calling him Joshua every time he sees him.
- In The Pit, he finally learns Jake is Joshua's son.
- Kee-Oth apparently had a longstanding rivalry with Joshua and Margaret, as they kept a picture of him on the door to their office in "Joshua and Margaret Investigations", and Margaret used his picture for target practice with her crossbow. The Demon Blood Sword is seen in Margaret's weapons room, despite it not being created until after the events of this episode. This might be a sword made from the blood of a different demon.