The title really says it all.
What if Jacob and Nemesis are keepers of the island, and Smokey is just their 'guard dog'. They both use the monster to keep track of the island and it's inhabitants. That would make sense, seeing how erratic the Monster's actions have been: Jacob uses the Monster to judge people, the Nemesis uses Smokey to kill people he thinks in unworthy. Both control the Monster however they please (plus the monster can be summoned by other people, but not really controlled).