Name: Danny Summers
Other Names: Danny Summer
First Appearance: The Tomb of Dracula (vol. 1) #1 (Apr. 1972): "Dracula"
Number of Appearances: 5
Ally: Frank Drake
Employer: Summers Inc.
Occupation: business owner
Worked for: Dracula
Note: Frank Drake's wealthy friend
Danny Summers had been a good friend to vampire hunter Frank Drake. But later, at a time when Drake thought all the vampires were destroyed from the Earth, Drake went to Summers for a job. But Drake learned that Summers was working for Dracula, who wanted him to kill Drake. When Drake finally confronted Danny, he learned that Danny had been put under a spell by Dracula. Danny claimed he had no choice but to follow the vampire lord's orders.
Drake also learned, with the help of Brother Voodoo, that all of Danny's workers on a dig in Brazil were zombies that Danny had summoned using voodoo.
The extent to which Danny was volitional in all this is unclear, but he was indeed dabbling heavily in voodoo and he was also a vampire servant.
One could easily wonder what (if anything) Danny did to bring such supernatural activity into his life. Drake eventually left Danny without destroying him or anything (Danny wasn't actually a vampire). But Danny doesn't seem to be enirely innocent in all this. It seems that the whole bit about using zombie slave workers for his business in Brazil was his doing and his idea, and not something that Dracula foisted on him.
Suggested links for further research about this character and the character's religious affiliation: