SI'Ur'Boroth claimed to be ageless and had a connection with The Subterraneans although it is unexplained as to what his relationship with them is.
SI'Ur'Boroth was created by writer Joe Kelly and artist Ed McGuinness for the Spider-Man/Deadpool series.
Major Story Arcs
SI'Ur'Boroth arrives to Weirdworld, with Subterraneans acting as his heralds. There, he encounters Deadpool and Spider-Man with the former interrupting his speech. When he is distracted, Spider-Man attacks SI'Ur'Boroth with a drilling machine which subsequently breaks as spine.
As the two heroes escape, The Subterraneans attempt to heal their master.