Daimon Hellstrom, aka "Hellstorm, the son of Satan" hasn't been heard of publicly since World War II where he was an active mystery man working alongside the Allies to combat the nefarious plots of Hitler's supernatural evils. He mainly worked out of England; however, when the Spectre put the kibosh on the super world, he abruptly disappeared and was not heard of until recent days.
Mystical circles may know: Over the years, a Hellstorm cult popped up and drew many fanatical followers who would gain residence to Hellstrom's home in Massachusetts. There they operated for many years until recently when those in the know could have heard that they were all slaughtered by the return of the master of the house. Those circles may also know that Hellstorm has recently returned to the Earth plane.
General populous may know: Though he's kept a low profile, he has re-established his supernatural investigation agency and runs a weekly ad in the major newspapers of the world. So if someone wished to hire him to investigate a supernatural event, they would dial 1-800-SON-OF-SATAN.
Other circles of influence and power may also know that Hellstorm is active in the New York branch of the Hellfire Club. Spending time in the club and enjoying his return to splendor.
The best way to establish RP with Hellstorm is to page him and say, "Hey, let's RP." If he's around and able, he'll be glad to get into a scene with just about anyone. Please keep in mind of his motivations. Parties, debauchery, exorcisms, demon or angel eviction, supernatural supers and capers, destroying evil, and all around fun.