What does Sultan mean?
From Arabic 'sultan', originally an abstract noun meaning 'strength, authority, rulership' (from 'sulta', power/authority), later a sovereign's title. Note: 'ruler/authority', and distinct from 'malik' (king) proper.
What does Hadi mean?
From the root h-d-y (ه-د-ي, 'to guide, to lead rightly'), meaning 'guide, leader, one who directs to the right path'. Al-Hadi is also one of the names of God; as an everyday human given name it is common and is presented here in that sense.