Kiba- His younger son. Kiba is the result of an affair Elias had with his older son's, Liam's, wife. It is unknown if Kiba is aware of this.
Liam-His elder son, who's wife had an affair with him... their relationship is probably strained by this.
Denahi- Elias doesn't necessarily get along with him, but they do have a romantic relationship of some sort.