There was no real leader in the Demonic Faction, just the stronger and weaker clans that everyone was aware of. However, there was a legacy.
The Demonic Faction, being the way they were, wasn't a faction per se, but due to the growing strength of the Dark Faction and Light Faction, they needed to do something otherwise risk getting wiped out.
The Neverfall Clan was well respected because it was their leader who had brought all the major clans together to agree practically an alliance to go against the other Factions.
There was still no clear view of which clan was the strongest, but all of those that had been invited by Belil were considered the strongest.
This consisted of the Neverfall Clan, with Belil at its head. The Behemoth Clan, the biggest clan in the Demonic Faction, with their leader Sha Mo.