On warlock/fighter, I recommend not likely with Hexblade but as a substitute Fiend. The overlap goes away and temp HP for your personal kills is especially excellent for melee fighters (plus better level talents much like the destruction resistance are by no means not likely to be beneficial). I recommend https://messiahgnzpz.wizzardsblog.com/18622699/detailed-notes-on-dungeons-and-dragons-paladin