Aim Death from Above correctly and you'll cover quite a distance because your character will travel diagonally downwards instead of just a vertical drop. Also, if you happen to have the Helm of Inmost Light, then you can even further improve the range of your attack. Since this helmet grants you Death from Above for free, you can use the freed up spot for equipping Shockwave. So, after you successfully aim your Death from Above, your Fist of Havoc will send out a shockwave which travels towards the direction you're facing upon impact.