A vampiric Decepticon Pretender who has lived on Earth since prehistoric times. Leader of the Decepticons at the start of Masterforce
A truly vicious Decepticon, Blood's actions were kept in check under the rule of Emperors of Destruction Megatron/Galvatron and Scorponok. But after their deaths (Scorponok returns alive and well later in Masterforce and takes leadership) he was left with no one to give him orders and acted as he saw fit. To this end he found a small group of Decepticons who would follow his psychotic whims, these included Gilmer, Dauros, and the Seacons. These Decepticon psychopaths first made their presence known by attacking a cruise ship full of innocent and defenseless humans and murdering all on board.
Blood was not done with his sadistic rampage however, next he and his followers attacked Tokyo, Japan, but were met by the Autobots led by Metalhawk, who stopped Blood and his crew from murdering more humans.
Blood, Gilmer, and Dauros escaped however and remained a constant threat to the Autobots throughout the Masterforce series. Eventually Scorponok resurfaced and acted as the emissary of Devil Z, Blood became a loyal follower of the Destron's demon leader.
It should be noted that:
Blood is not the inheritor of the Emperor of Destruction title, and is probably not even in line for that rank, he only leads a group of like minded murderers. This makes him the first Decepticon seen leading the other Decepticons at the start of a Transformers series to not hold the coveted Emperor rank. (Not that he seems to care)
Blood says he has lived on Earth longer then humans, this is true of all Transformers who arrived on the Ark or Nemesis, but apparently Blood did not remain in stasis and actually lived on Earth while the other Transformers slept.
Blood's vampire alt-mode may not just be for show, he has been implied to actually drink human blood while in that form. If he indeed does it may just be for his deranged amusement more then an actual need to.
Blood's action figure was renamed Bomb-Burst in the United States as Hasbro felt the name Blood may hurt sales due to conservative parents. His vampire pretender shell remained unchanged however.